I'm in the same boat.
Although, I have a ton of experience with pixelling Final Fantasy Tactics and other similar styles which are iso, I think.
Still, I have a project that happens to be in the early sprite design phases, and I'd like to see what people post here regarding iso styles. The one on my avatar is one of my first attempts.
If I were to suggest something, however, it would be this: head to Pixeljoint and gather as many Isometric references as you could dream of, study them thoroughly, and then begin your own style from that.