Thoroughly establish in your mind the thought that all sentient beings equal to the limits of space were your parents, and you their child. Have the view of friends and enemies as being equal.

If you do that, you will have immeasurable equanimity that is said to be like a sage throwing a banquet. When a sage throws a banquet for guests, he throws it for everyone, without any regard for high or low class, relative or unrelated, good or bad. You should have equanimity toward the objects of compassion, which are all sentient beings who pervade all of space. Until you are able to do that, train your mind.

-- Ngawang Tenzin Norbu