Alright here's the secret. For the best constancy and taste use 85/15 meat.
Season it with Lawry's on both sides. Not too heavy or all youll taste is salt.
Make sure you fry it in an already heated pan, because it sears the meat locking in the flavor when you first put it in the pan.
Flip the burger every 2 to 3 minutes, do not smash it with the spatula because it will squeeze the juices out and dry out your burger.
7-8 min worth of cooking should be medium rare, 12 to 15 will be well done.
*edit*
oh and if your trying to make the healthiest burger, this probably isnt gonna be for you