You haven’t provided a method.
Obviously, I'm not a fundamentalist Christian (so this is not really relevant to your point about the Bible), but there are methods of deciding what is useful or true about what religious texts offer in general. The common misconception is that a cultures religious text must all be either true or false and if something appears to be nonsensical or bizarre then the whole thing must be discarded.
Since I'm not a fundamentalist I don't have those fears or limitations to which information I can use or accept. But one thing is good to understand about religious or spiritual literature, that there are features that can be systematically categorized.
When contemplating scriptures in general, whether that be the Bible, the Upanishads, the Sutras, Tripitaka or whatever the case may be there are distinct features and those are literal history, places, events and things. Then there are stories, analogies, metaphors, figurative speech, symbolism and tales. Then we have teachings, and teachings can come in all forms of literature through anyone of the former I mentioned. Then we have what I call applicable principles or practices, these are practical teachings that can be applied to the self which could result in observation.
Typically, some of these features are either useful or simply can be discarded as irrelevant. I don't have any expectations of scriptures that require perfection, to me that is quite absurd so TBH, I tend to use more commonsense rather than being pressured to accept that everything must be true or that if I don't accept everything as true, I must be a heretic or a heathen.
As well, I have no pressure of being swayed by dogma or religious indoctrination so generally speaking, I am free to simply evaluate the contents and make sense of them by taking what is useful and laying aside that which is not.
Basically, by breaking down scripture into categories we can decide what "MUST" be true and what emphasis we put on accuracy in comparing content with reality. Being careful not to define reality where we limit it to our own biases. To be intellectual honest and open minded we must leave room for variations in our interpretations of what reality is and is not, what exists and what does not.
I don't put much emphasis on story telling as being useful, perfect or true, to me they are typically either difficult to judge as being true are obviously simply a tale. To me they are useless in terms of judging what demands of perfection I put on them. In other words, there is really no way for me to know the intent of the authors and whether or not they are trying to pass off falsity as being something true. What I would look for in stories and tales would be any underlying message, principle or metaphors in relation to our experience of life which should typically be pretty obvious. Other than that, I don't care much for stories unless they contain significant meaning.
Literal history should be straight forward, we should be able to match descriptions of literal places, events, people and things with various external sources. Not such a big deal there. I mean, it may not always be black and white but to me it's not something one needs to place much emphasis on perfection in terms of its usefulness.
Now, when we get into teachings and application this is where I start to really pay attention to details and importance because it reflects the heart and core of what it is the source is attempting to offer the recipient. This is also where you need to be the most open-minded about reality because teaching requires a student willing to learn something.
Understanding thoroughly that these features of literal history, stories, teachings and applicable practices will be intertwined throughout the entire piece of literature, this is very common especially in ancient spiritual texts. If one is not aware of this, they quite frankly should be. The Bible, as an example, is notorious for weaving in and out of literary styles and so commonsense goes a long way here. Again, not putting much emphasis on perfection and being free to use that which seems useful.
I can give examples of each feature of course, and since most people here are fixated on the Bible, I'll give a couple examples of each category I mentioned.
Literal history is again, very straight forward we know in the Bible that there are accounts of literal people, places and things as much as we can verify them. If we can't verify them oh well, it's not something we will use to determine whether or not the Bible contains truth.
A story would be as follows....not assuming whether the story is literal or figurative there's not much we can do about that unless we have some documentation confirming whether or not it is literal. For the purposes of this post, it really doesn't matter because a story is a story, there's either something of value within it or there isn't. It's not really the setting or role we are putting emphasis on it is the message behind it.
We can take the story of Noah's flood for example, the story of Job, the story of Samson and Dililah, the story of Moses or Abraham, the story of Jonah ect ect..these are accounts we have no real way to verify so we simply take them as stories. There is no real reason to put any more relevance on them because they are no teachings or applicable practices, they are simply tales that may or may not have significant meaning and again, if they do it should be obvious. Arguing on whether or not they literally happened is IMO silly. It would not be a reflection on whether or not the Bible has something to offer us.
Now let's get into teachings as an example, this is where we want to begin to put more emphasis on the contents and whether or not there is any truth involved or could be involved. A few examples of teachings would be like these passages as an illustration keeping in mind these are just random quotes, but they should reveal some contrast between what we know or do and may not know or do....
Matthew 5
39 But I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also.
40 And if any man will sue thee at the law, and take away thy coat, let him have thy cloak also.
41 And whosoever shall compel thee to go a mile, go with him twain.
42 Give to him that asketh thee, and from him that would borrow of thee turn not thou away.
43 Ye have heard that it hath been said, Thou shalt love thy neighbour, and hate thine enemy.
44 But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you;
45 That ye may be the children of your Father which is in heaven: for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust.
46 For if ye love them which love you, what reward have ye? do not even the publicans the same?
47 And if ye salute your brethren only, what do ye more than others? do not even the publicans so?
Colossians 3
2 Set your affection on things above, not on things on the earth.
13 Forbearing one another, and forgiving one another, if any man have a quarrel against any: even as Christ forgave you, so also do ye.
14 And above all these things put on charity, which is the bond of perfectness.
15 And let the peace of God rule in your hearts, to the which also ye are called in one body; and be ye thankful.
Romans 8
4 That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit.
5 For they that are after the flesh do mind the things of the flesh; but they that are after the Spirit the things of the Spirit.
6 For to be carnally minded is death; but to be spiritually minded is life and peace.
7 Because the carnal mind is enmity against God:
James 1
13 Let no man say when he is tempted, I am tempted of God: for God cannot be tempted with evil, neither tempteth he any man:
14 But every man is tempted, when he is drawn away of his own lust, and enticed.
15 Then when lust hath conceived, it bringeth forth sin: and sin, when it is finished, bringeth forth death.
16 Do not err, my beloved brethren.
17 Every good gift and every perfect gift is from above, and cometh down from the Father of lights, with whom is no variableness, neither shadow of turning.
John 4
23 But the hour cometh, and now is, when the true worshippers shall worship the Father in spirit and in truth: for the Father seeketh such to worship him.
24 God is a Spirit: and they that worship him must worship him in spirit and in truth.
John 3
3 Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God.
4 Nicodemus saith unto him, How can a man be born when he is old? can he enter the second time into his mother's womb, and be born?
5 Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God.
6 That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.
Here are a few examples of application/principles that can be applied to the self...these are things that are applicable that should reveal something we don't have that we could have....
Matthew 6
33But seek ye first the Kingdom of God, and his righteousness; and all these things shall be added unto you.
Matthew 7
7Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you:
8For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened.
Matthew 10
38 And he that taketh not his cross, and followeth after me, is not worthy of me.
39 He that findeth his life shall lose it: and he that loseth his life for my sake shall find it.
John 14
15 If ye love me, keep my commandments.
16 And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever;
17 Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you.
18 I will not leave you comfortless: I will come to you.
20 At that day ye shall know that I am in my Father, and ye in me, and I in you.
21 He that hath my commandments, and keepeth them, he it is that loveth me: and he that loveth me shall be loved of my Father, and I will love him, and will manifest myself to him.
23 Jesus answered and said unto him, If a man love me, he will keep my words: and my Father will love him, and we will come unto him, and make our abode with him.
John 6
35 And Jesus said unto them, I am the bread of life: he that cometh to me shall never hunger; and he that believeth on me shall never thirst. (Figuratively spoken of course).
John 4
10 Jesus answered and said unto her, If thou knewest the gift of God, and who it is that saith to thee, Give me to drink; thou wouldest have asked of him, and he would have given thee living water.
11 The woman saith unto him, Sir, thou hast nothing to draw with, and the well is deep: from whence then hast thou that living water?
13 Jesus answered and said unto her, Whosoever drinketh of this water shall thirst again:
14 But whosoever drinketh of the water that I shall give him shall never thirst; but the water that I shall give him shall be in him a well of water springing up into everlasting life.
15 The woman saith unto him, Sir, give me this water, that I thirst not, neither come hither to draw.