I average probably 3 or so sacks a game playing as TCU, what I do to get them (once had 5 out of one guy in a game) is I almost always play as a d-lineman, and always play as a rusher (Safety, CB, LB). But you need to get your shedding moves down, use the right thumbstick, it works wonders, I'll shed off of OT's that are way better than my DE, and DTs almost always stomp on O-line.
But you also need to change your blitz every time, I run maybe 50% of my plays as blitzes (5+ guys rushing) over a whole game, but I might only blitz the same guys (other than D-line) 3 or 4 times a game. So if you call a LB blitz, have your next blitz come from a safety spot, or even better call a CB blitz from the short side, those guys are awesome.
Also another technique if you're blitzing a guy from outside the box is to engage the furthest out O-lineman with your DE so he has an easier path to the QB. For example if they have no TEs and you're blitzing a Safety from outside of the Tackle you'll want to engage your DE on that tackle and not the guard, then work out so if the guard blocks your Safety your DE will have a free path after he sheds the Tackle, or inwards and engage the Guard so the Safety has a free path (depending on the play, and you can switch those moves to add confusion)
Like I said I love the blitz, I run my whole Defense on it, and I'm always 1st D in the nation against the run, and usually 2nd or 3rd against the pass (just like in real college football
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