Turning in circles
Twisting, turning, bucking, banking, spinning, and spiralling up to the sky .. everyone seems to have their own style, a characteristic way of moving through the air. I am also learning how to fly in the SA sky, and by the reconning of a bird, with 1000hours airtime, I am about a one-year-old eagle (sometimes turkey), barely out of my puberty-feathers. But I often get to cloudbase, so maybe my advice on tweaking the most out of your turns, to save altitude and stay in the lift will help you.
Most harnesses have some form of cross-bracing built into them, either as integral angled straps that run from the chest-strap, or as add-on adjustable cross-webbing. The purpose of the cross-over is to re-distribute the pilot's weight during large collapses of the wing. Instead of falling towards the collapsed side of the wing, the pilot is suspended by the cross-brace which transfers the weight to the wing which is still flying.
All well and good, except that many pilots fly with cross-overs that are too tight (they should bow loosely during normal level flight). A cross-over should only begin to take effect when your seatboard has tilted past 45degrees. If it is carrying your weight before this point, then your weight-shift turns will have no effect, making your flying less efficient. Your glider will also tend to suffer more asymmetric collapses, as the rigid position of the harness does not tilt to absorb the roll movements of the wing.
3.2 Chest-strap settings
Apart from keeping you in the harness, the chest-strap determines the distance between your carabiners. A wide chest-strap (>38cm carabiner to carabiner) will result in a more sensitive harness, easier to weight-shift, with superior ability to read the feedback from your wing. At some point it does become too sensitive, and it is unnerving having a chest-strap that flaps in the breeze. 38cm seems to be a good compromise. A tight chest strap (<38cm) reduces sensitivity, and because the carabiners are now inside your body-line, the harness has a greater tendency to spin (yaw). This becomes problematic during (uncommon) violent collapses and negative spins, as the pilot can experience twists in the lines due to harness rotation.
3.3 Brakes, speed to fly and flying fast
Your glider's sink rate is minimised with around 1/4brakes applied (one good kink all along the trailing edge of the glider). So if you're trying to get as high as possible, as fast as possible, theory suggests you should have 1/4 brakes on in the thermal. So how do you turn? By shifting your weight. How much? Lots. If that isn't enough to keep your circle within the thermal, then you need to employ the negative turn, not pull more brake than 1/4 on the inside wing.
3.4 Negative turn
The negative turn offers a very tight circle when executed properly. The first stage is mentioned above - the bow-back. Some wings bend slightly, in others you can just feel the tension in the wing, waiting to be released. So first - 1/4 brake both sides. Second - weightshift to the side of the turn you want. Then third - release the outside brake. This allows the wing to swing around on the inside brake which is still held at 1/4. To trim the circle to shape, dab on the outside brake when you want to straighten up (you think the core is in front of you), and release it again when you want to tighten (you're in the core!), maintaining your weight-shift throughout.
3.5 The Albatross, the Crow and the Eagle
The albatross is a huge bird which thermals exceptionally well. Their technique seems to be to keep their wing as level and rigid as possible. They use just a tweak of their wingtip feathers and a slight shift in their wings to initiate a turn. They are graceful and inspiring to watch. In light, wide thermals they are masters. Their technique equates to keeping the wing as level as possible, slowing the wing to minumum sink on the brakes, and using very little weightshift, maybe a gentle negative turn. Yet their technique doesn't work in all conditions. When the air gets choppy, and the lift punchy, scrappy and strong, their only hope is to link up many pockets of lift in their wide circles, using their awesome glide angle to do what paragliders can't. To hold onto the one, strong core requires a change of approach, and this is where the crow comes into its own. Swooping and carving, banking and climbing, slipping their wings around in tight turns almost at the point of stall, then swinging out in a joyous, speedy circle. This technique equates to using lots of weightshift, flying fast and actively, tightening your turns quickly when you feel lift, throwing the glider around. Here I often abandon the negative turn in favour of flying faster, just weightshift, then inside brake to initiate the first, climbing turn.
The eagle, oh majestic master of the sky, blends the two techniques, and seems an albatross in the late afternoon mellow sky, and a crow at midday. The challenge of flying like an eagle is partly learning how to blend the Albatross and the Crow to get the most out of the sky you are in. The other part of the challenge is catching something for lunch.