Bear, if you are still getting absolutely nowhere heads-up, try playing the exact opposite way, just randomly out of the blue...
This may sound a bit nuts and feel strange at first but there is some method to the madness!
When we have a very tight table image and our raises get too much respect, we can often-times just start raising high with hands which we don't want our opponent to call with at all simply for the fold equity. With the blinds only getting higher it is a perfect time for us to start stealing, especially if they have been running us over previously when the blinds were lower.
Then, it's just a matter of raising less or limping and calling with premium hands that we actually want to induce calls and raises with in order to get more chips into the pot. We can lightly bet or even check any flops which we hit strong, and then bet stronger on the flops which we don't actually want to continue to showdown with most of the time.
The other important thing to remember is, if our opponent is aggressively playing with around a 75% range, and we've only been playing around a 25% range, it is probably okay to call their all-ins or push them all-in when we have caught something we like and they have caught something they appear to like.
It's a bit hard to generalise as every opponent is different, but as soon as we work out what kind of style they are playing we can exploit them. But yeah, if all else fails, we can just play the exact opposite way to how we have been playing. At the very least we'll put some indecision in their mind and mess up all of their assumed
tells about what kind of player we are.
Heads-up is also a lot about the variance so we shouldn't be too hard on ourselves if we do lose a few in a row, even when playing too tight. It is common for loose pros like Tom Dwan to have bad swings of 5 or 6 heads-up games in a row.
Anyway, I'm probably repeating useless information by now so I'll just leave a quote from my favourite heads-up pro player, Huck Seed:
"A lot of the time, when you are heads-up with a good player and they check the flop, it usually means they have something."