There are many methods to pack up a wing; this is the one that I use all the time. I like super-light, super-simple. So although concertina bags are very useful, especially for competition gliders and gliders with lots of reinforcing, I'll show you a method you can use if you don't want a concertina bag or haven't got it with you. It's a simple folding technique that keeps the leading edge protected and compresses well.
You pull out the centre of your wing, lay it out flat. Clip your brakes on. I leave a metre of line off the trailing edge.
Keeping the lines on top of the glider, do a little S fold along the trailing edge, bringing it in towards the centre. Do this on both sides folding it over, three or four cells at a time. That's just a rough fold that gets the tail of the glider neatened up, you fold it over and squash the air out of it, working towards the leading edge. Then bring your harness forward and put it on top of the folded portion of the glider.
You can do this next bit with a strap but I've gone even lighter and got rid of the strap. Coming around to the front, if I pull on the cells the harness is pinning the back edge so I can get a nice bit of tension, and I can do my leading edge concertina folds (as one normally would for a concertina bag) by gathering the nose cones. Because I've got that little bit of weight on the glider, it helps me get them lined up nice and tight.
I push some of the air out of it and step over the wing so I'm facing the leading edge with the wing between my legs. I use my feet now to trap the wing and give me a nice tensioned section at the front of the glider. All the nose cones are still nicely folded in the front. Whilst pulling it forward, I bend it around to the left and fold it against itself. This works on my particular glider because it has short reinforcing rods in the leading edge. If your wing has very long reinforcing, you might want to start the fold only after the end of the reinforcing, or make the tight fold and then stuff your flying jacket into the centre of the fold to give it a wider arc.
Using my feet I can pinch that again to tidy it up slightly just by folding the loose glider fabric inwards, before pulling it forward and creating another fold in the same direction. The result is that all the nose cones are all lined up in the centre (I keep my hand against them so they don't move). I then lift the whole thing slightly off the ground and trap the wing between my legs, ready for the bag. Try to keep the bag lined up with the nose cones so when you push the air out you are keeping that nice fold.
You're going to have one little piece left over, its just the tail, which I fold over the top, down on the outside of the bag. That's not critical, unless you have lots of long trailing edge reinforcing. It's usually only the leading edge that's critical to fold neatly. Because I put the bag on in the right direction it's safe to sit on the glider, squash the air out, and the Advance Compressbag allows me to get the packed shape much tidier. All nicely packed away, ready to go in the backpack.