[cshude]

Something that I've done before is to pick a chord (I picked Am7) and write a song that uses that chord somewhere in the progression. What you'll end up doing (at least until you can hear the chord in your head before you play it) is start playing every chord you know next the chord you picked to find something that sounds good, then move from there. It's a very organic way to create a progression. Yes, you can consult the Circle of 5ths charts to get some ideas, but by just sitting there and noodling around, you can come up with some unusual combinations that can sound great. Matty's also right about suspended chords adding a lot of spice to a tune.