1) Make friends with the person
2) Act as if you're a sucker
3) Sweet talk them
4) Kiss up to them, but not too much
5) Ask them to help you through the trade
6) Let them think they're taking the lead while making the decisions yourself
7) Always say that you're too insecure to give them account info/$ first (you'll be more successful if you act as if you're a noob at trading/selling)
Be humorous
9) Get personal
10) Most important! Either be consistent with being smooth, or choppy
If you need any clarification, please ask me.
I am reposting this because I put it in the wrong section, my apologies.
IF you have any suggestions, please add them.
EDIT:
11. Be respectful when talking on aim.