Reinforce qualities you want pressure to reveal.

Pressure does not build qualities. It exposes whatever is already there, in whatever condition you have left it. So the work is done in advance, in the quiet periods, reinforcing the things you want to find still standing when something difficult arrives.

Decide which two qualities you most want available under strain, and practise them deliberately while nothing is wrong. Calm, honesty, generosity, whatever they are. They will not appear on demand if they were not there beforehand.