Again, let’s say we’re cultivating metta towards ourselves (i.e. we’re doing the first stage of the meditation practice), establishing a good, healthy, positive self-regard as a basis for loving others.
As you sit in meditation, recall a time when you felt good about yourself. You may have just been in a very good mood for no apparent reason. Or you might have just scored a significant achievement.
Recall every detail of that time. The more vivid the experience, the more likely it is that you will recapture the emotions that you experienced then.
Recall what you were wearing, the things you saw, how you held your body, any scents that you smelled, the things people were saying.
Remember the details: the texture of your clothing, the brightness of the colors you saw, tones of voice.
The more vivid your recollection, the easier it will be to re-experience the emotions you had that day.
If in your meditation practice you can tap into your memories in this way you’ll help bring about the arising of positive emotion generally and of metta specifically.