You can't practice compassion, because compassion is not a technique.
arises or it doesn't. You can't conjure it up. In fact,
compassion more likely arises when you're not
trying to be compassionate.
This is why Jesus said, "When you give to the poor, don't let your left hand
know what your right hand is doing." And according to the Sutras, Buddha
said, "When the Bodhisattva performs compassionate service, there is no
concept of 'compassionate service.'"
People who pride themselves on being social activists sometimes complain
of "compassion fatigue." But our burn-out never results from too much
compassion. It results from too much trying, too much effort to mimic
what we imagine compassionate people must do.
The greater spiritual practice
is just to let the moment Be, without attempting
to become anyone more noble, anyone more selfless, anyone other than we are.
If we act spontaneously from Presence, compassion will arise without practice.