I still hang on to L2 when my guy has the ball, or I'm trying to deny a passing lane. R2L2 to shuffle quickly, but I've had a tendency to overadjust and let my man drive past me. So most of the time I just hold L2 and give some cushion vs my guy, but not far enough that he can take an uncontested jumper. Good slashers will still get by half the time. I'm maxed on def awareness and quickness, with the defensive anchor personality badge, plus the shutdown defender and pick pocket 3 signatures. I've tried the mind games and enforcer badges and they seemed to help, but no space for them now.
To tip a pass, body up on your man (L2) then hit [] when the pass is incoming. Your player should lunge and try to tip the pass if you time it right. To dive for a loose ball I think it's just [] when running after the ball but I can't seem to do it consistently (might just be me).