My wife loves venison liver, me not so much...but I get in a lot of trouble if I don't bring it home.
We usually brown bacon, then flour and season a well rinsed sliced liver, brown in the bacon grease and then cover with catsup.
The best liver comes from young deer. This years liver was from a mature buck, and it was inedible. I had also shot older does that were not worth cooking, which may be your concern. Also, it does not age well. We wont eat the liver if it is older than a day, and never freeze it. it just doesn't keep well (not going bad, just ...flavor changes. )