>>27425112I go by What Pokemon I haven't already used. There's no Pokemon that I dislike, so everything is fair game. If I've used it before in another game though, that Pokemon will drop to the bottom of the list.
I do also keep in mind their types and prefer not to have overlap, and Pokemon that don't evolve are usually less of a priority than ones who do simply because they can get boring fast.
I've found a lot of unexpected favourites this way just by being open minded.
