I think in reading the Bible from cover to cover, you really can see the things that are consistent all the way through and the things that are particular to certain places in time. The Lord gave certain commandments to Israel in order to separate them from the surrounding culture and as a symbolic foreshadowing of Jesus' coming. And in the New Testament in Galatians, Hebrews, and Acts in particular, the Apostle Paul (and Peter in Acts) addresses the relationship of the Old Testament laws and rituals to the New Israel, the Church.
Also, in reading Deuteronomy and Leviticus you can see laws that are not only symbolic or ceremonial, like the eating of certain foods, but are about justice and righteousness and our relationship to one another. So the ceremonial laws of the Old Covenant are fulfilled in Jesus and no longer hold, but the laws about immorality are consistent all the way through. Homosexuality in the Bible is a sin from Genesis to Revelation. So is adultery, greed, envy, neglect of the poor, etc. And also, there were things that God allowed in the OT that didn't necessarily reflect His ways, like men having multiple wives. And Jesus even says that God permitted divorce because of "the hardness of your hearts," but it still wasn't His will.
I think for the whole Bible to make sense we have to get what the whole story is first and that the Bible is not just a collection of various commands, but an unfolding narrative.