If it is a construction project, I rely on knowledge I've gained through the years working. I know how to do a fair amount. However, I ask, ask, and ask people who are in other trades that I work with for advice. If it's auto related, I'll ask my buddies who do auto work regularly.

Anything else, I try to find people who have experience in what I'm trying to do......see the pattern? Lol. Most importantly, after I get the advice I need, I DO THE WORK! When I do the work, I learn. The more I learn, the less I have to rely on others.