Things I've noticed:
Sharp checkering on a frontstrap can sometimes snag your cover garment and make it hang un-naturally, just be aware of it as a possibility. Usually happens to me when getting into the car so I just adjust in the car and no problems.
If it's windy out, hands in the pants pockets can keep your cover garment from flying up over your head.
If you're just starting out, make sure your wife/GF/whatever knows that you're carrying and knows the consequences of exposing your gun. My wife was trying to show some friends of ours something on my back, or something to do with my pants, don't really remember what, and lifted up my shirt exposing my gun in a parking lot. Fortuantely nobody else noticed, the wife got a good scolding. All I heard about it from my friend was "So, I see your permit showed up."
Wear your rig around the house a lot and try lots of different positions. I started off thinking appendix carry would be the best, but ended up carrying at about 9:30 (shoot lefty) once I tried everything out for a while.
The leather squeaking will go away eventually, and no, nobody really notices.
For using a public toilet, when seated, keep your waistband just above your knees on your thighs, keep your feet about shoulder-width apart and spread out your knees to keep tension on everything. If you must you can buckle the belt around your knees, but I've been able to keep everything in-line with just a little knee pressure. Right handers would be more likely to need to buckle unless they run the belt through the pants the "girl's" direction with the tail of the belt pointing to the right instead of left when all buckled up.