Get visitor tt1 brk font, in my experience you can make it fit almost anything.
Personally I like making flashy, bold text that's really one of the main focal points, or right next to one. Like scr said, go with rule of thirds, but do one of two things.
A: Put the text right at/near the main focal point where everything's going on
B: Put the text in a rule of thirds focal point with not much/nothing going on at all (make it a main focal point)
Don't go halfway.