When I was studying composition many years ago at Melbourne Uni (to complete my undergraduate music degree) I had a few lessons with Brenton Broadstock. One of the things he said that stuck with me was (and this is not a direct quote) "If you write something that you like, repeat it". Though this seems like a very simple idea, I have never forgotten it and often thought about repetition when writing new music. A small phrase, a chord progression, a musical gesture. If there is something that stands out in your music that you like, don't just allow it occur once, repeat it. People instinctively like what they know, or what is familiar. In repeating a passage or fragment of music you inadvertently make the music more familiar to the listener.