Easiest entriy/exit: Yellow Submarine, Tori's Reef, some of the house reefs, and the stretch between Belnam and the airport. If you are diving the southern reef (below Belnam) go early. As the day progresses, the wind usually picks up and the southern entries become a bit more difficult because of the surge.
Entry/exit: A trick I learned on Bonaire (after flubbing around on severtal shore entries). Watch the waves and count. Usually there will be a pattern of increasing wave height with several much smaller waves following the largest. Once you figure out the pattern you wait for the largest and then enter as it's receeding. Quickly go out far enough to float (chest high) and put your fins on.
Keeping hydated: Soon as you get there buy a couple of 1 or 2 liter bottles of water. Remove the top drink a little and put the rest in the freezer. Bring it along and you will have ice water to drink after each dive. A 2 liter usually lasts me for 3-4 dives.
As far as dive sites - there ain't no bad.