Decide on the method that is most intuitive for you to play triplets. You can use a number and letter scheme such as "1 e +, 2 e +". The "+" sign is used to signify the word "and." This makes it easier to write the numbering in the music. You could use the sound "Trip-ul-let," in which each word is a different sound, or you could simply divide the notes equally across the beat.
Count the triplet out loud. If you are using the number and letter system, use a consecutive number for each beat. This system makes it possible to write the beats in the music. The other systems may also be used, but they present problems with notation.
Practice with a metronome until you can get three evenly spaced notes over the course of a beat. Start at 72 beats per minute, then slowly decrease the tempo. It is harder to count triplets at a slower rate.