Find a shop that has a Good selection of basses.
Sit down, and play through a bunch of them.
Objectively review them, what you like, what you don't like, how they feel, how they sound (ok, this one is very subjective!).
The point is to try out a bunch of different basses, and eliminate ones that don't float your boat, and find things that you like.
If one speaks to you more than the others, take the plunge.
Don't worry about styles, scales, pickups etc., just try to find something that suits you.