I flag high (6 feet or so) and I flag low (2 feet or so)..depending on the terrain...and through a variety of sources I came up with a pretty good system...and had a suprise along they way...sit back relax..and let me tell my story

I tried the fishing line thing..worked well, until the high winds on top of the mtn messed em all up...what to do...put on the thinking cap..and pulled files out of memory bank....I took a
12" pc of 24 gauge wire...wrapped it around my finger, made a loop...on the other end..I bent a 1/4" 90
stuck a turkey feather with a heavy sewing needle...stuck the lil 90 into the hole and duck taped it tight.
Then I took a clothespin...drilled an 1/8 inch hole in it...took 10" of 12 ga wire...bent a tiny 90 in it too...stuck the 90 in the hole (just below the spring) and wrapped duck tape around the handle tight also....then I inserted the 12 ga through the loop made...in the 24 ga...and made another loop..and wrapped it tight...cut the excess off FLUSH!!! <---very important
Now I have a turkey feather clip on a branch flag...the light wire allows movement with very little wind...and this rig takes about 3 seconds to attach at a set....
Now the suprise....a Buzzard wing feather...is even better than a turkey feather, I happened on a dead buzzard....and clipped his wings, thinkin his wings are designed to soar for long distances..and I was RIGHT!!!! If you just LOOK hard at a buzzard feather..it starts to swing on the wire...and to acknowledge some previously stated complaints....the top is all-but-black.....and the bottom is a whitish-grey GREAT CONTRAST!!!
Hope this helps....
Scott