#1
Alright so I've had my Gibson SG Special for a while now, and i still haven't gotten around to changing the strings. I know i have to really soon, and I'm planning on it. The thing i noticed was that since i've had the guitar, the 3rd string generally sounds worse then the others. It sounds like...really twangy, and always just a little bit out of tune. Is there anything I could do, or is there any kind of strings to get for this not to happen?
#2
probably needs action/intonation adjustments and a new set of strings, something heavy like gauge 10's or maybe 11's.

search google for "setting up a gibson SG" and give it a good going over

it also might help to give it a really thorough clean too.