first start with the people you are called upon to love by your station in life - family, spouse, kids, co-workers, fellow citizens, fellow parishoners etc. Love them in the ways described, striving to eliminate jealousy, envy, impatience, whining, bitchin’ & moanin’, back-biting, gossip, detraction etc.
Then look for people who are impossible to love because they are dirty, diseased, sinful, or just plain nasty, and love them in the same way. You may be able to do the first paragraph on your own, but you will never be able to do the second without Christ, so seek Him and model yourself on Him, and let Him bestow your cross on you, and bear it gladly every day.