Ok, here's a few...probably obvious to most.....
If breaking hard on the runway after landing, retract the flaps (not the gear) straight away, else its easy to burst a tyre, and you stop quicker.
In a heavier aircraft, like the Seneca (compared to single) add a couple of twists of nose up trim on final, helps in the flare.
Turning onto final, say out loud the expression 'Final clear check the gear'. This was taught to me and now I can't get it out of my head...
Cheers
EA