I typically mix lean mean (venison) with pork because it has plenty of fat. The only exception to this, is when I make smaller sausage links and cold smoke them. Smaller link sausages are easy to make and honestly, more convenient since they will store for much longer (less fat to go bad)
Pork Shoulder is the cheapest, "fatty" pork.
It's best to mix a lean mean with a fatty. Lean - white chicken meat (skinless), venison, turkey, some beef. Fatty - pork, some beefs, lamb, dark chicken meat.
You can mix other products like cheese, oils, lard, liquid smoke, etc.
Seasoning makes all the difference in the world. Salt is a good sausages best friend. I find that fresh herbs from the garden that are dried, will flavor your sausage much better than store bought. I grind my herbs with my M&P and then add them. Don't be afraid to experiment.
Don't run the meat through the grinder too much, or the meat will be way too dense. Once or twice with a larger die is fine. Be careful with chicken or it will get pasty.
If your meat (especially lean) is hard to mix, mix a little lard or oil to the meat. Or add more fatty product.
Not all casings are the same, do some research on the grades. For beginning, go with a 36(ish).
Use the right size horn for the size casing you have.
Don't worry about a loose sausage. You can make up for it later when you twist the links. You'll get better over time and learn what's best for you.
Poke small holes up and down the sausage. This will allow air to escape when you twist the links. Also, you don't want air because when you cook it, the sausage will burst (like most store bought sausages do).
I typically separate my links after a few hours in the fridge. This allows the flavors to move throughout the meat, but also allows the twist to dry a little. The last thing you want is for the meat to push out the end.
I haven't made sausage in quite a while... now I want to do it... thanks alot. LOL
