My wife and I have 24 packs of burger in the freezer so far this fall. Our goal is always to not have to buy "cow burger" from the grocery store before next October when we replenish our supply. As we cut up our deer we always have a "burger bucket" for smaller pieces we trim off steaks or roasts, and many times we'll just steak up the backstraps, a few round steaks off the hind quarter, and burger the remainder of the quarters - we use a lot of burger.
Advice? Trim out your venison as best you can - remove all fat, tallow, suet, silverskin, blood vessels etc - it will make a huge difference in the taste. Also we use the grinder attachment for coarse ground burger vs the finer ground.
Now you'll get many different opinions on this, but we do add good quality pork to our burger - the ration we use is roughly 2 parts venison to 1 part pork. We've found that when we don't add pork there isn't enough grease to fry up a burger, for instance. Personal preference and to each his own. We'll buy boneless pork butt or in a pinch will even use pork steak. We don't use the pork fat or connective tissue - just the prime marbled pork. This is blasphemy to some, but I'll put my wife's venison chili, spaghetti sauce, or buck burgers up against anyone's anytime.
Our process goes like so - we do a grind mixing the venison and pork, and then mix that up by hand (nothing like burger squishing between your fingers). We then do a second final grind and package that up in freezer paper - 1.5 lb packs work best for us.
We were taught how to make our own burger by a local (UP) butcher, and we've been doing it for about 10 seasons now. We started out with a hand grinder, and then bought the grinder attachment for our KitchenAid mixer. Lots of folks like the Cabela's grinders too
Hope this helps - Good Luck and Enjoy!