Easy way for some titles:
Get a second controller, go into Versus, Player vs. Player, Character doesn't matter for second person. Crouch-block with second controller and hold that position. Now do his neck slice (back, FP) into any linker to ender multiple times and you should get the overhead titles with ease. This also helps with overhead trials.
Go into your fight profile, read up on which ones you're either close to finishing or haven't really done much to. The most missed is usually the overhead one.