How do you place your initial settlements in Settlers of Catan?
If I'm the first player, I always go for the most powerful settlement, since I have no idea what I'll get when it comes back around to me.

If I'm last, I grab spots that based on the numbers and the available ports will get me an advantage.  I also like to try to place the second settlement on a brick/wood combo so I can start with a road.

The other positions are variations in between the others.

In general, I try very hard for number diversity.  I love it when I can get both a 6 and an 8 placement.  Next in line is at least 3 of the following: 5, 6, 8, 9.

The final thing you have to look out for is that you have somewhere to go.