Fly as many types as you can! I had about 15 types by the time I had 150 hours.
The more different types you fly, the more you will realize they are the same. I'm talking about the general actions and principles.
You will also better appreciate aircraft with nicer handling properties. Getting into taildraggers will further improve your skills and appreciation; do that as soon as possible.
You my like to consider two techniques. Either develop a generic checklist which will cover all types or develop a scan which goes from one side of the cockpit to the other so that every item is in the correct setting for the situation. I prefer the latter.
Consider BUMPHFF, on downwind, in a Tiger Moth. Brakes-none, Undercarriage-none, Mixture-none, Propellor control-none, Hatch and harness-still closed and on (because no-one has left their seat or climbed out (and what if they had?)), Fuel-Still on ('cause the engine is still running) and sufficient, Flaps-none.
Great. But it doesn't cover the slats which should be unlocked (they should have been locked for aeros).