3-4 Regular formation kills runs to the sidelines. Unless your opponent is running two-TE sets, just lock a LB on the RB. Unless you're coming in with a hard-hitting LB, wait til help gets there and focus on cutting off the sideline before you attempt to tackle.
I stay in 3-4 (regular, over, under, solid) unless I've got my opponent on 3rd and 6+, then switch to Nickel 5-2 or Dime depending on the situation. 3-4 is vulnerable up the middle, but excellent against a lot of these quick read, short passing schemes that lots of people use.
Subject: Nickel-Normal D