Heads-up, especially in tournament play, is all about
equity PRE-Flop. This has been said afew times already, and I'm not going to repeat it. You need to push your edges. And if you are against an aggro villain preflop, the chances of you needing great to flawless preflop play rises. The good news is that against a predictable aggro/maniac opponent, hand charts and % are really all that is needed in SNG NL.
But if you play against an aggro who just wants to play that trash postflop too... Here are a few considerations.
What you need to assess:
a) The blinds/ante structures
b) The level you're currently at
c) Stack sizes
d) Reads, wich can be harder to have than say @ 6-max or full-ring
e) Your image, wich can even be harder to gauge
Basically, you have to assess every one of these points. What makes every decision more difficult is that during a normal SnG, you might butt heads with someone a dozen times before bubble and high blinds. This means that your reads might be more specific because there aren't as many "white-noise" hands that come to completion: ie. random KTo against 56s on 954r flops to naviguate through to get your reads. The palette of hands the villain will play to the flop is smaller, wich means the "hitting" flops aren't as plentiful.
There are two ways to compensate for this:
a) Either try to not play postflop with tricky hands, wich will not work against a good (or even bad) aggro opponent.
b) Switch gears often in borderline situations where the EV is hard to gauge (nearing 50/50) and milk mercilessly the very obvious +EV situations.