I've always used lean ground beef. If you have a bunch of liquid that doesn't look like it's all fat (or you just simply don't care if theres a bit of extra fat in there -which is generally where I'm at lol) You can outright skip the water, and just add and bullion cube. Then just let it simmer until you've only got a little liquid left. Sometimes the onion has alot of liquid in it, and sometimes it seems like some ground beef is more liquidy, so you may or may not need the water.
Like Matuta said, if you let it get to dry, they wont be as delicious.
I'm going to add this bit to the first post too. Great questions guys!