It certainly isn't an easy game, which is the appeal to me! I get thumped about 50% of the time.

It is possible to win quite easily by taking advantage of known issues with the AI. I would guess from what you wrote that you don't like this approach either. The toughest part of the game is the Early period, or the first few years of any starting period. If you can get through the early stages without getting discouraged, you should be OK.

Success at first also depends on which faction you choose. Although the game rates them as Hard, I think the Spanish are the easiest to start with - good provinces and easy to defend.