The first step is to rebuke ourselves for having such attitudes about the Word of God (and I bet this corruption has been manifest to each of us, I know it has to myself), and renew our resolution to receive it as that, the very Word of God; confessing that any boredom, despair, presumption, ____________ (fill in the blank with any wrong reaction) is due to ourselves and not the LORD.
Then, we spend our best efforts meditating and considering why the LORD would have it so in His Word to us, knowing that it is for our good. It is also not necessary to view everything "through a gospel lens," that sentiment itself subject to all manner of disagreement on definition, etc.
We might consider, for example, the specificity of the commands for the creation of the tabernacle... we might meditate upon the fact that the LORD is meticulous about how He will be obeyed, and what He requires in worship. The LORD God of truth is precise, and does/commands all things well. He alone is worthy, then, of our worship. We might, from this, consider our own failures ably to worship Him aright, apart from a perfect Mediator.... namely, the LORD Jesus Christ.
When we come to passages about genealogies, we might meditate upon the importance of church membership, and how these lineages may point to this.
In Numbers 36, we might consider a larger principle: Moses was brought an apparent problem, with regard to the inheritance of the daughters of Zelophehad, but that it was not a problem, rather an opportunity to ascertain the mind of the LORD (which we have testimony that He did, vv. 5-6, 10). They learned something with regard to the preservation of their earthly inheritance, and how it might be preserved. There doesn't have to be an immediate "gospel lens" from that passage to justify its existence, and -yet- there can be much meditation upon the mercies of God in His particular revelation to His people such that He does not leave them without direction.... certainly meditation upon THAT will lead to gospel uses.
The LORD has designed for our mediations upon the Scriptures -when not being contradictory unto or distracting therefrom- to be inexhaustible. This is a feature, not a bug, that we might be like the godly man in Psalm 1, mediating upon His law, day and night.