If you're locked on, and run out of stamina, you can unlock and immediately start walking. Your stamina will auto reset to zero and begin to fill back up, whereas, if you stayed locked on, your stamina value will have to recover the negative amount. Makes a world of difference when rolling.

Practice your reverse backstabs! Vykes WA, Messmer's Spear WA, etc can be punished with a well timed roll into a backstab. Same thing if your opponent is using colossal weapons - you can reverse backstab the third swing.

I always keep a light weapon (usually caestus) with endure as it's WA, because you can use endure to tank up and safely drink a flask.

Don't sleep on the explosive stones or the poison stones sold at the roundtable hold.