My son Joseph is a professional singer and dancer. I've watched him perform on many occasions, and frankly I'm baffled at how he can move expertly around the stage for an entire number with apparent ease. Each show comprises hundreds of individual moves linked together in choreographic phrases, much like musical or literary phrases. To me it seems impossible that he could remember them all in the correct order and perform them seamlessly. If I were on stage, I'd be stopping between movements to remember the next motion, and it would look awful.
I once asked Joseph how he remembers all that, especially on the occasions when he is singing while he dances. He said that he practices long hours, repeating strings of movements over and over until he develops a "muscle memory," an ability to perform without thinking. He says his muscles just remember what they're supposed to do, without his consciously thinking about the next move. The performance becomes as natural to him as walking is to you.
Similarly, the more we practice being loving, the more natural it becomes. We develop an emotional memory, where we just know how to respond in loving ways. Behaving selfishly becomes increasingly unnatural--even seeming ridiculous--just as Joseph doesn't become confused in the middle of a performance and run off the stage at the wrong time.
In the beginning of your learning to love, you'll make lots of mistakes. That's all right. Just learn from them and keep practicing. You'll make individual loving decisions much more often, and then you'll string them together into coherent patterns of loving attitudes and behaviors. Eventually it will become a dance of great beauty and personal satisfaction.