What soil is best for growing watermelons?

This upcoming spring my friend and I were planning on growing some good watermelons. Now, my family and I have always included a few watermelons in our small family gardens, but the yield tends to be unpredictable. About 2 years ago we got six good melons, just last year we only had one mealy little melon. I was wondering really, what soil is best for watermelons? My friend and I are wanting to grow a larger variety (if that makes a difference, I heard the small Sugar Baby melons like sand but I haven't heard much about larger melon varieties) and we want to get a good yield this year. We will be tilling a new patch instead of using our usual gardening patch, does that make a difference also? We have a variety of soils: Rich black soil on a creek bed, clay-like soil, and more. Just wondering if anyone could offer some good insight on growing good, large melons. Thanks!!! :)