Understand What Went Wrong
It’s very easy to die in a game and flame your team mates, look at your hit log and recognise that a few HEAT rounds were fired at you, and push all blame for your destruction or potential loss on those two factors. If that’s what makes you happy and you’re not interested in improving, that’s as far as you need to go.
I would, however, put money on the fact that the sole reason for your death wasn’t actually because the enemy hit the 2 key. If that’s all that was required to win the game, everyone would be Unicum right? And yes, I’m sure your team’s performance wasn’t the pinnacle of gaming ability. They’re flawed human beings, and expecting a flawless performance from them is a mistake on your part. There’s always something that you, personally, could have done better.
Watch back your replays with an open mind, look at everything that happened. Were you outnumbered on a flank? Then perhaps you should have switched flank and pushed the other one. Were you too passive? Help your team out on the front lines next time – playing a Tank Destroyer doesn’t mean never leaving the Red line.
If you don’t know what went wrong, get an experienced player to watch a replay of yours and give you feedback. I’d be happy to watch a few replays if you upload them to WoTReplays and leave them in the comments below if you genuinely have no idea what you could improve on.
If you're struggling with how a certain shot went in, a firm grasp on Overmatch and Normalisation mechanics can help.