You need some of this to season your meat:
Don't press the burger down when it's grilling. I see a lot of burger n00bs do this; it just squeezes the juices out. Flip it shortly after the blood starts to come out of the meat on the top. Add cheese thereafter, and put a hat (a lid) over it to melt the cheese. If done right, it will come out juicy.
When it comes to beef, I usually use Costco's hamburger pack. It comes pre-portioned, but not necessarily in a complete patty shape. It's just enough to hand-spank a patty. When I worked in a brewpub, we only used pre-formed patties, but they were Oregon Angus beef patties (yum!). Don't use overly lean beef or, for that matter, overly fatty beef. There is a balance to be struck. Overly lean beef will fall apart. Beef with a higher fat % should be handled as little as possible and kept cold. Generally, when you're spanking a burger, you should handle it as little as possible.
There are a lot of other things you can do with a burger; I believe there's a thread somewhere here that addresses the topic.