Christians may do good things in their lives, but the reasons we do them might not be exactly what we think they are. We don't do them so God will like us and let us into heaven. And we don't do them so God will like us here on Earth and give us stuff, or at the very least aim the lightning bolts at some sinner instead of us.
We do good things in our lives because we believe God calls us to do them. We even call it "God's will," because we believe we're doing what God wants us to do. We say that we want to live lives where God's will governs our actions, our words and even our thoughts.
Of course, saying that leaves us trying to answer the question, "What is God's will?" And that one's not easily answered.
Christians have thought about God's will in different ways. One suggests that God has a perfect plan for the world and for your life, and that you have the responsibility of discerning that plan and following it. Because it's your responsibility, you can choose to say no to God's plan. If you do, then God will readjust his plan in light of your choices and you have another chance to choose. This idea seems to take into account the reality that God can redeem suffering and wrong choices, and it offers more room for human freedom, but it still seems to have a healthy slice of "programming" about it.
Another idea suggests that God has a general plan for what he wants you and I to do, but it's not specific. In fact, God will allow us to block out our lives as we see fit, but he will offer us the chance to let him guide us in what we do. If we don't, that's our own lookout, but it's not the best way to do things and we're likely to find that out.
Both of those ways leave us with our question we started out asking, though: How do we know and do God's will? How do we know what guidance God offers or what plan he has?
When we ask that, we have to be sure we really want God's answer. A lot of times we want God to tell us to do what we already wanted to do anyway. We just want God's OK on it so if it goes wrong we can blame him. Or we want turn-by-turn directions that outline the right step at every possibility so we don't have to make those decisions on our own.
The truth is that God has already outlined his will for us in ways that cover most of the decisions we make. Think of the Ten Commandments. If you know them, you know what God wills in a whole lot of circumstances. "Lord, this enormously attractive woman asked me to come to her house when her husband was away. What is your will for me in this situation?" God isn't going to come down and Gibbs-slap you and say, "Number six, meathead!" because he's already told you what you need to do.
If those are too much, then remember that Jesus focused on just two: Love the Lord your God with all your heart, soul, mind and strength and love your neighbor as yourself. When faced with a course of action, we can ask ourselves if it rises from or demonstrates a love of God. Does it demonstrate love for our neighbor? Does it demonstrate the most love possible for God or for our neighbor? If it does, then it is probably an action within God's will.
These guidelines don't help us with some of the choices we make, but when we look at them we might understand that God is OK with either option. God may not have a preference about which job you take as long as you honor him first in all that you do no matter where you work. If you can, then take the one that seems best to you. If one offers more money but you intend to tithe from that higher income, then there's nothing that says God wants you to take the lower paycheck.
I think that sometimes, we tie ourselves in too many knots trying to "figure out" God's will, when what we probably need to do is to further study his word and learn we can already know that will. Ah, some say. But what if we choose wrong? Well, then we immediately go to hell.
Of course we don't! See how silly that sounds when we say it out loud? And yet all the time we act like it's the truth! If for some reason we choose wrongly and it turns out we didn't discern God's will and we admit that and rededicate ourselves to following that will, what happens is we are forgiven, just as we would be no matter what we confess to God.
We sometimes say when we try something and it fails that we're going to have to switch to Plan B. I have no doubt that I've goofed enough times to run the alphabet through and then some. But God is still with his Plan A: Loving me, offering me forgiveness when I admit my failure and redeeming even my mistakes so that I can try again. If I remember and live in that, I've got a pretty good pipeline to knowing and doing his will. As well as help when I get it wrong.