I wish this caveat were attached every time someone mentioned the "once it compiled it worked first time" bit. Not because there's no truth in the works-if-compiles idea, but because getting smug about it is sure to bite you in the ass sooner rather than later.

Now that I've said that, I'll state what should be obvious (and probably is to many/most): failure to compile due to type errors is a big clue I am thinking about something incorrectly or incompletely. It's not like I just twiddle stuff until it compiles. I look at it and say, "Duh! That was dumb of me!" It's like using Unit Analysis working out a long physics problem... errors in your thinking about it are very likely to show up in unit analysis. The chance of you coming up with a bogus equation that passes unit analysis is pretty small. When it doesn't pass, you have a good look and find where you went wrong rather than merely tweak.