I am far from the best/brightest here but here is my opinion.

I am looking for something which is conisistent. It doesn't have to win each day but it should win most weeks and most months. I am also looking for something that is logical. If I have a rule I want to have a reason behind it. For example wide barriers are underbet by the public so they usually are a good starting point for value.

As far as testing it I have seen many models but I think the only one worth using is a real live test period of several months with small stakes. If it has been consistent in the past then it should be consistent and win over a test period of 3 months.