Intro: What follows here are some of the things I've learned about windsurfing, with more to come later. I'm a forty something windsurfer; and I didn't really get started in windsurfing until I was forty something. Someone once told me that I was too old to learn how to jibe. Wrong! From what I've seen here in Corpus Christi, windsurfers can learn how to jibe at any age. At first inexperience, and now aches and pains have kept me from rough water and big air, so I spend my windsurfing time going fast and practicing jibes on the Laguna Madre. At 6'1'', 170lbs., I find my older model F2 Xantos 295 (a great board) serves me well. I usually try to sail when the winds are 20 mph and up so I can use my older model Gaastra RAF sails (they're easy to handle and jibe).
You can beach start in very light wind by using the mast as a sort of pole vault to help you onto the board. Apply downward pressure through the boom, mast, and mast foot to the board (mast foot pressure -- mfp) as you hop onto the board. Sheet in some as you go to keep the sail from back winding you as you move it forward. Pump the sail if you need more pull from it to help get you up on the board. With practice, you should be able to beach start in the lightest of breezes.
In high winds, maintain a defensive position with the body well back and upwind of the sail so you won't get launched forward and over the other side. Keep the sail angled over into the wind and close to the water to decrease the power. Sheet in slowly and only when you're ready to have the power in the sail pull you up onto the board. Then hop on, hook in, get in the straps quickly, and zip.
When first learning to use a harness, start out in winds of about 10 mph and work your way up. The wonderful instructional video "Turning Point" with Peter Hart is good for learning harness and footstrap use as well as many other windsurfing skills. At first, set the harness lines long enough and the boom low enough so it's easy to hook in and out (when you get good in strong winds, shorten the harness lines and raise the boom for better performance (for more information on harness line length, check out the article on harness lines in the windsurfing tips section of the CCWA web site)). In light winds, to save the arms, you can use longer harness lines and/or a lower boom to remain hooked in with the sail in an upright position.
Hook in with a forward movement of the hips and not by pulling in with your arms. When hooked in and powered up, commit your body weight to the harness to match the pull in the sail. Relax your arms and grip the boom lightly with your hands (relax that death grip on the boom!). When well powered up, commit your body weight fully to the harness and sit into it like sitting against a wall. The power in the sail will hold you up. Aim for the position assumed by the fast sailors in the photo gallery--hanging out in the harness, arms extended and relaxed with the sail raked back. Yes, if you suddenly lose all your power, you may end up falling back in the water; but experience will help you to handle those situations. If you feel you are about to be launched over the other side by a strong gust, get in a defensive position lower and further back, and sheet out as needed. If overpowered, lean out over the water more, and angle the sail lower over the water to cut the power. If you do get launched while hooked in, try not to damage your sail or yourself, get unhooked quickly, and start all over again. With experience, your frequency of getting launched should decrease dramatically.
To start, while planing, try to place your front foot at the front edge of the front strap and your back foot at the front edge of the rear strap. Keep the board level with your back foot and slide the toe of your front foot around the front of and into the front strap. When ready, do the same with the rear. Keep looking where you are going. Don't look at the straps. If you miss a strap, move your toe around and try again when ready. Keep your weight on your toes and off your heels. Try to get in the straps as early as you can before the board gets going too fast. If the board wake tries to take your back foot away as you go for the back strap, go for the strap earlier before you get going so fast, or head upwind some to slow down, then go for the strap. This becomes less of a problem with experience. Concentrate on keeping the board flat, and bear off the wind a little if you keep rounding upwind when going for the back strap.
You don't have to be going fast to get into the straps. As long as you have good planing power potential in the sail, you can get in the straps early and go. In overpowered conditions, you can even waterstart with your feet in the straps, power up the sail, hop onto a plane, hook in, and zip (a little tricky, but it works).
When you get comfortable with the straps on the big board, you can try going to a smaller board with the straps forward. When you get good with this, you can move the straps back to suit your sailing style.
Next, get the feel of your rails at planing speed. If you are going fast, you have learned to sail the board flat from rail to rail -- if you dig that windward rail, the board will tend to head up and slow down. In the jibe, you need to use the leeward rail to carve the turn. So, learn to use those rails to carve through the water like a wake board or surfboard. Start with S turns at speed. Then do your stops with fast, carving 90 degree turns upwind (always look before you do turns). Now try 180 degree turns downwind. If you don't flip the sail, you'll be back winded and dumped at the end. When you learn to flip the sail at the right time and stay on the board, you've done your first jibe. It may take a while before you can make most of them, but practice really helps. Then, to plane all the way through most of them takes more practice, good technique, good power in the sail, and good speed. Good luck.
Speed: To get the most speed out of your gear, you need to maximize power and minimize drag. Rig your sail full enough to get good power and flat enough for good speed. A too full sail is slower from too much drag; and a too flat sail has less power. When fully powered up, sheet in fully to or near to the centerline of the board and rake the sail all the way back until the foot of the sail touches or nearly touches the board -- "closing the gap". Keep the sail well upright. Pulling the sail down over the water decreases power. Keep your front hand just in front of the harness line -- keeping it up near the mast chokes off power; and adjust your harness line position so you sail well sheeted in without effort. Keep the harness lines short and the body position fairly upright -- long harness lines with the body hanging way out over the water = slow. Keep the boom positioned as high as is comfortable on the mast -- this increases power; and drive the power in the sail into the board with good mfp.
Position the footstraps and mast base as far back as is comfortable to decrease the area of the board in contact with the water and decrease drag. Keep the weight on the toes and off the heels to keep the board flat from rail to rail -- digging that upwind rail slows you down.