I'm a diver who ventures out on my own to practice skills. Ideally, you should be doing this in a pool, but sometimes that just doesn't work. As far as choosing a location, I would pick one that is relatively popular, and has calm water (no current). A bay, cove, something like that. And if it's early in your diving life, I would log the dive. Why not? You'll probably end up practicing for a while, then swim around, observing what's around you. I would also note that it was a skills dive. I like to practice buoyancy, check to see if I can handle/use all the gear I have strapped to me (especially cutting tools, and if I've added or changed a configuration) and other procedures (i.e, inflating and shooting my safety sausage, for example). Have fun!