Well, I use Xirrus Wifi inspector to get an idea of the wireless access points around mine and what channel they operate on. I know there is another program out there that does something similar, its name escapes me at the moment. You could install one of these programs and see what other AP's are in the area and what channel they are operating on. This also allowed me to test the signal strength with antenna placement. I still haven't decided though, if I should be trusting what the router reports as the signal strength, what windows reports, or what Xirrus reports. I suppose I always go with what reports the strongest connection, just to satisfy my need for improvment. LOL.
Sometimes changing that can solve some minor issues. As well, antenna placement seems to make an impact. I remember a couple times trying to get a 300Mbit connection and for the life of me I couldn't. Everything met the requirements. Then I played with the positions of the antenna and bingo!. With me, even the slightest adjustment to the antenna would either be met with grief or with joy. Some recommend and antenna placement like so: \ | / but in my case I could only be happy with some unconventional antenna placement that resembled something close to /\| or /|\. I suppose it all depends on the location of the computer and router and how the room is shapped.