If you want to learn ZZ for just 3x3, work on EO-Line. I personally find the bad edges in the F face first, B face next, S layer last, then predicting where DB and DF will be after EO. F2L is ,similer to zz, but not exact. Work on new algs that keep EO for each F2L pair, get used to making pairs for the 2x2x1 blocks that have white ontop. LL is exact same thing, except you have EO.
For EO cross, I would strongly recomend trying to use it like cfop solvers use X cross. My rule is I do it if I can find a soultion for EO cross that will not add more then 5/4 moves to my soultion for my EO line. When there is a good solution, I don't pause as much because I don't have to look down at DR and DL.