Guidance and the Word of God

When I was on summer camp last year, there was a seminar on guidance which really helped me in the way I think about how to make decisions in a Christian way, rather than just being a Chrisitan who makes decisions. Essentially, decision-making was split into three categories: obedience, wisdom and trivia.
Obedience was where the Bible is clear on whether or not I should do a particular thing. For instance, the Bible says 'Do not get drunk' (Ephesians 5:18), and so as a Christian I should obey that clear command. My decision as to whether or not to get drunk is a matter of obedience.
Wisdom was where being a Christian should affect my decision, but there is nothing in the Bible making it obvious which decision I should make. For instance, to 'abstain from sinful desires' (1 Peter 2:11) - in other words, not to put myself in a position where I know I'll desire to sin. So if there's a party where I know everyone else will be drunk, it's a matter of wisdom as to whether I go. If I go, I know I will be tempted to get drunk - so the wise decision is not to go. (On the other hand, I may decide the wisest decision is to go, not get drunk, and therefore live differently in front of my friends).
Trivia is decisions that just don't matter to my life as a Christian. I'm at a party, I'm having one drink, should I have a glass of wine or a beer? The Bible doesn't say anything about which, nor is it a matter of wisdom - it's a trivial decision.

Thinking about decision-making in these categories is, I've found, very helpful. The one I always slip up on is the 'wisdom' area. Obviously, when the Bible clearly says something, that pretty much makes my decision for me. But it's very easy to relegate matters of wisdom, where I should be thinking 'Christian-ly', to a trivial matter, because then that means that I don't need to think about it. Particularly in the area of sex and relationships, it's important if we think something is trivial to be honest about why we think that...is it because it really is trivial or because it's a matter of wisdom that I'd like to be trivial so that I can do whatever I like?