The
trade thread is your best bet to find stuff (start on the last page, those are the current 'want adds'). As far as communication goes, use the private messaging system. Most deals are done thru the mail, but if you and the other person are going to be at a future event together then you can cut out the shipping charges and deliver the goods in person.
As for ability level, don't worry about it. Every tourney has seasoned veterans all the way to beginners. I've played in 4-5 tourneys yet I still get tooled on by the new folks... what does that say?