Rabbit hunting is very easy, and a good excercise (the way I hunt). Just walk around until you scare a rabbit, it will sprint away from you. Even if you don't see it, it will run away. With a shotgun, you can shoot it, but if you are rifle hunting just wait until it stops. They normally stop about 30 yards away from you and just stare at you incase you walk towards it then it runs again. Lucky for people hunting rifles, they stand still.
I love rabbit hunting because I can just walk around, unlike hunting almost everything else where I just lay in a bush.
In my experience, I have had sucess at all times of the day. Yaa the middle of the day gets a bit slow, but you can still have sucess. I live down in San Diego, if you wanna come with me some time just message me. Driving about 30 minutes to San Diego County's deserts has some of the best rabbit hunting around. Especially in late spring, early summer.