B-Reversing your recovery can be a good way to position yourself forward coming back on stage if that's applicable to the situation, but mainly I would just say try your best to avoid accidental L-Stick inputs. In higher level play this is one of the biggest things that hurts people coming in and I think a lot of people from all levels of play ignore it too much. Flicking the stick and letting it return to neutral on its own can cause snapback if it's done too hard, which can cause accidental turnarounds and such.. this was a huge problem in Melee before UCF and such.
Go into training mode and practice stuff involving turnarounds, starting with basic turnarounds (simply flip your character, no movement, just face the other way.. over and over as fast as you can, just edging the stick) and slowly work your way up to things like RAR's. This should improve your general use of the L-Stick overall and will help avoid accidental turnarounds. Also try to follow L-Stick with your thumb, when you can, even if just barely with the pad of it.. this is to avoid snapback.