As for the 2.4 GHz band the best channel to use is the one that is not overused by your neighbors, channels 1,6,11 have wider bandwidth so they suffer less from interference, though they are NOT the best ones to choose in all cases.
For the optimal results, I recommend you to use this WiFi Analyzer app.
This app will analyze your nearby WiFi networks and will till you the best channel for your case in order to avoid interference.
