I try to adjust the strength of my handshake, depending on a few factors, but mostly related to how hard the other persons will shake my hand.
I'm not trying to match the strength of their shake, just adjust my own. The objective is to make the other person feel more comfortable.
I start with a strength based on some stereotypes (for example, slim women generally have weaker handshakes than big men), but adjust the strength during the shake if I feel my initial strength wasn't right.
Whether this makes the other person actually feel more comfortable is difficult to know, but it makes me feel happy that I've tried.
However, it does mean that I feel a bit sorry for people who have a crushing handshake - what do they think they are doing?