To adjust saddle height, I put my armpit on the center of the saddle and hope that the second joint of my middle finger reaches the crank spindle. I might have a short leg-to-arm ratio, because I've read a rule of thumb that says the tip of your finger should reach the spindle, but this rule works for me.

I set a non-leather saddle to be level. I set a leather saddle nose-up.

I still haven't found a rule for myself for the fore-aft adjustment. That probably depends on various factors.