The short answer is that the start world is able to give you a jumpstart toward one or more specific strategies (the military world is probably the best example), but you can still play a very successful strategy that does not revolve around (get it?) that world.
I often make the decision about whether to commit to the start world pretty early on. A very common strategy, I'm sure you've noticed, is to play Explore on the first round. Between my starting four cards and my first explore draw, I will try to find a strategy that will get me ~50% of the way through my tableau (not necessarily from the cards in hand, but from the powers and phase plays I expect to focus on). If there's one that the start world helps, that's usually weighted pretty heavily.
If a strategy coalesces in my hand that the start world does little to help, I'll usually still go for it.