Guitar tip: Cleaning up your act

In order to sound as professional as you can, when playing single note lines, mute the strings you are not wanting to hear (usually 5!) with a combination of your fretting hand finger tips (usually index, for the string lower than the fretted string), and the (under)side of index finger for the higher strings when possible. You should be able to single out the 1 note you want and strum across the 6 strings and only hear the 1 note and 5 'muted'/'chocked' strings. Next, you want to let the thumb flesh of your picking hand gently rest on the strings you have already played (when ascending low to high strings), acting as a 2nd form of muting. Basically, don't focus all your attention on the notes you want to hear. Focus as well on the notes/noises you DON'T want to hear. This takes time, but well worth the effort as eventually it becomes the 'way' you play single notes, and your playing will forever be 'clean'.