The 3 things are flight socks, a heat pad and stretching techniques.
The flight socks (compression socks) are by far the most important. So these go up about as far as my knees and they drastically improve any symptoms below the knees. You can also get supports to compress the thighs and hamstrings as well. The flight socks do lose their tightness quite quickly so you have to keep buying new ones maybe every week or so. Also sometimes with my older used flight socks I tie them as tight as I can around any area that is uncomfortable and this almost completely takes all of the uncomfortableness of my RLS away.
The heat pad is for my lower back. If I lie down then I will always get uncomfortable legs and have the need to move them. However, with a heat pad on my lower back, the need to move my legs greatly diminishes and sometimes even completely disappears.
I believe that the reason why the flight socks and the heat pad work is because my RLS is caused by poor circulation and I think that this is the result of a problem in my lower back.
I watched a documentary on RLS the other day and at some point every single sufferer featured in the documentary could be seen to be putting their feet at odd angles and putting their ankles under pressure to try and stretch their calf muscles. By stretching the muscle, you are aiding its circulation and so I believe that this is why it helps.
I have found that stretching an affected area can relieve the symptoms while it is being stretched but then very soon after (sometimes immediately) the uncomfortable feeling returns. Flight socks greatly aid circulation and can be worn comfortably during the day or night whenever needed and as often as needed and they have basically the same affect that you would get from stretching the muscles.
The third thing which helps me is stretching techniques for the lower back and hamstrings which can be found on youtube. These helped a bit in the short term and a bit more after several weeks and then after a few months there seemed to be a fair amount of improvement with both my back and my legs being less stiff and my RLS being less severe in general.
I have suffered from RLS for about 10 years (since age 21) and while the techniques that I have outlined aren't a cure, they make my quality of life, and particularly my sleep much better.
These techniques have really worked wonders for me and I really hope that they will help others as well.
If anyone has any questions or comments then please feel free to email me at firstname.lastname@example.org