Yeah, I can't be bovvered to post the photographs yet again of my home made reflector, - they've been here twice before - but get some polished aluminum sheet, cut a bit about 6" by 12", curve it roughly into a parabola section and fix it some 2"-3" behind the wifi antenna. In my case I shaped it to steer the mystic rays away from the front of the house (road passes there) and instead blast 'em across towards my bedroom where the activity takes place. The computation activity, that is, these days. Gave me a couple of extra bars on the smartphone.
Messing about with home-made reflectors and signal strength is almost as much pleasure as messing about in boats, but dryer.
P.S. I have a few surplus-to-requirements satellite dishes here, range in size from 60cms to 100cms (oval so offset), hanging the smartphone from the LNB mounting and pointing the dish towards our local town achieves amazingly increased responses even though the frequency is quite different.