Be careful and don't mistake the wick under the bobbin for lint -- that can be painful. I put oil in the wick more frequently.
I have a 7700 so I open the door on the left side and clean out all the lint around the takeup lever, etc. I also clean out the area around the bobbin -- sometimes I find that my serger tweezers work well to get the hard to reach lint.
EasyPeezy's link is good -- I don't like using q-tips because of the lint they release. I use pipe cleaners and the brush that came with the machine. Don't put any oil on plastic parts.