If I’m struggling with positioning, I find it useful to position against something else, at least as an exercise.
If I’m struggling to determine what a client is it can be useful to think about what they’re not to narrow the field a little. It’s counter-intuitive, but creativity needs constraints. Starting with a wide open field with no constraints makes it harder to focus, and good positioning needs focus. Once I’ve ruled a bunch of things out, things that the client is not can help to bring what they are into better focus.
Competitive positioning can be useful to clarify your thinking, but beware of defining yourself only in opposition to others. That puts your strategy in the hands of other people. If all you do is not what those people are doing then you’re easy to manipulate. A competitor could make it look like they’re moving left, safe in the knowledge that it’ll force you to move right, straight into the trap they put there for you.
Competitive research is a tool, so use it, but don’t neglect all the other tools you have at your disposal.
And remember: sometimes terrible people have good ideas. Focus on the idea, not the source.