Aren't you going to Ethiopia? You won't have much to worry about lion-wise.
Everyone's already given great photo tips, so I'll just say this about Ethiopia: stay relaxed and keep your sense of humor. Ethiopia can be hard on certain travelers, and it's a polarizing country. It helps to not take things too seriously--"things" ranging from people following you all day screaming "ferengi ferengi ferengi!" to the sometimes-complex public transport system. It's one of my favorites though, and I can't wait to revisit someday.