I hate Pete's answer, too, because I think that once you know the basics of how to leave and return to shore, the best way to learn is by yourself, trial and error, in lightish winds up to 10 mph.
Here are my suggestions, based upon my own past experiences resulting from poor judgment.
If you do all those things, you will be safe to go out and play by yourself and learn on your own. Maybe other people will have additional suggestions, but these work for me.
1. Before you ever take off alone, you have to have friends around so you can practice capsizing your boat and righting it. It is important to know that you can right it yourself.
2. You also need to know whether you are able to get back onto the boat (from deep water) after you right it, and how and where to get back on when you are alone with the boat. (Best place to get on -- although not always the easiest -- is in the front, so the boat stays headed into the wind and doesn't turn off the wind and run away without you, or with you dragging behind.)
3. If the boat capsizes, do not ever, not even for an instant, let go of the boat. If it gets away from you even for a couple of seconds, you will not be able to catch the boat, because it will drift away from you very fast, even in fairly light air.
4. Always know where the wind is coming from. When you are in learning phase, it is best if you have an onshore wind at your departure/return point.
5. When you leave the shore, if the wind is parallel with the shore, ALWAYS head upwind from your departure point and do all your practice sailing upwind of that departure point. That way, if you have a problem, you will at least drift back downwind toward where there may be somebody who will see you and can help you. (This is good standard safety practice for ALL recreational sailors, regardless of experience.)
6. ALWAYS take a paddle with you on the boat (auxiliary engine).
7. Take a small anchor on the boat. Even if the lake is too deep for anchoring out in the middle, when you are single-handing, an anchor can be very useful for temporarily securing the boat when you come to shore.
8. ALWAYS take water with you.
9. ALWAYS take a jacket of some kind with you, even if you don't think you need it.
10. ALWAYS take a little tramp bag of tools, knife, and little pieces of line to fix things that might go wrong.
11. File a float plan with somebody -- let them know when you are leaving, from where, and when you plan to return to where.
12. If possible, take a cell phone with you in a waterproof pouch.
13. When alone on the water (or sailing with young children), I tether myself to the boat.
14. Put a Hobie bob on the top of your mast, so you don't have to worry about the boat turning upside down.
15. When you are first learning on your 4.3, alone on the boat, start out using the main only.
P.S. Once you are on the water, you will have no problems. It is getting the mast up and launching the boat and getting the boat out of the water and back onto the trailer that are problems for most women single-handers -- the land part of it.