When picking a starting position, make sure that you have room to grow while running into as few major enemies as possible. Grabbing a continent early on is great, but not that valuable if you don't have a path to that second continent, or at least some other natural border.

If you have the choice, selecting an area with many small continents can often work well; while you may play for a smaller prize each turn, your production will grow every turn as you get a new, small continent. Starting in an area with only a large continent forces you to fight for the whole thing when you don't have a large army and when you may not have much productive capacity.