[danbruc]

The most important point is the first one.

Ask yourself what’s the problem you’re trying to solve

Be sure that you understand it deeply, and that you at least have an idea of how would you know that the problem is solved.

But I think this does still not stress enough how important truly understanding the problem is. More often than not, the problem you are immediately facing is not the problem you should solve. When you are facing some problem, there might be a more or less obvious way to solve it. But then think again. And again. Is this really your actual problem or did you go wrong much earlier? If this is indeed the case and you can identify the true root problem, you will immediately know - not only will your immediate problem suddenly become trivial, but you will also see how many other things that always did not seem quite right could be improved.