I've never been a big fan of liver, but DW loves Chicken Livers.
Typically, we fry liver (Chicken or Beef). I've made Liver and Onions, but DW isn't a fan of onions as anything other than a minor player in a dish for flavor.
The only other way I've made liver and actually liked it is to cut the liver into 3/4 inch pieces and dredge in flower. In a skillet sauté some onion and bellpepper in a little oil until soft. Remove them from the pan. Add a little more oil to the pan, then brown the liver on both sides, about 2 minutes per side.
As the liver is browning, combine 1 can of tomato sauce, 1/2 cup water, and 1 tsp of Italian Seasoning. Mix well.
Once the liver is brown, add the onions and bellpepper back to the pan, then pour the tomato sauce mixture over everything. Stir a bit to mix it all up, and cook over medium-high heat for about 8-9 minutes. Remove from heat and make your plates. You don't want to let the liver cook too long or it will overcook and get chewy.
I like to serve this over rice (I'm a big fan of rice), but you could serve it plain, over noodles, or even slices of garlic bread.