I got this tip from a friend who was trying Weight Watchers a number of years ago.
If you are using ground beef in a recipe that requires cooking and then combining with sauce ingredients, this is great because you will not miss the greasiness and the flavor will not be horribly reduced.
Start with lean ground beef, I look for 90/10 or even 93/7 beef. This refers to the percentage of lean meat and fat that is ground up together when raw.
Now when you cook it in the frying pan, notice the puddle of hot, liquid fat. Normally I would drain the fat and return the pan to the stove.
My friend recommended that you drain the fat and rinse the meat under hot water. Then also use a paper towel to wipe the fat residue out of the pan to remove as much fat as possible. Return the drained meat to the pan and season.
This works really well for taco meat, sloppy joes, or chili.