I usually enter with my mask on and snorkel in my mouth, holding my fins, BCD should also be full of air (so you can stay on the surface). I put my fins on when i'm about waste deep in the water (you should be able to still stand, but also be able to float in the water so you can put your fins on) I use the snorkel to see what i'm doing in the water and not waste my air. Once your fins are on, you can start swimming on the surface to get farther out before finding a good spot to descend.
other tips: It is best to do a shore dive from somewhere you may have swam at before, just so you know a little more about the area. Otherwise, be sure to pick out a good land marker so you can remember where you entered from, and have a good idea of which way the current is flowing so that you have an idea of where you'll end up going (bring a compass).