What are some best practices to know about online trading?
A great deal of trust and good faith are required to trade online as it usually requires dealing with someone whom you've never actually met in person, going only on their screen name and written word.
Each member's page has a "Feedback" link where other members who have traded with this person can leave feedback, positive or negative, regarding their dealings.
Some other ways you can vet a potential trade partner is to look at their profile page. How long have they been a member on this site? Pull up their list of forum postings. Do they have good and respectful interactions with other site members? Look at their Friends list. Do you have a mutual friend that can perhaps vouch for them? Look at the completed transactions. Has the person already successfully completed trades on this site? You may also want to try reaching out to the people they've traded with to see if it was a positive experience.
It is important to negotiate all aspects of the trade during the planning stage so that there aren't any misunderstandings. This includes everything from the expected condition of the items, the shipping dates, the type of packaging to be used, and whether to purchase insurance on the package.
There are online companies that also offer consignment services for trading whereby each person puts down a deposit to ensure that both parties are satisfied with the outcome of the trade.
It is important to keep a clear line of communication during the entire process. Try not to leave anyone hanging, wondering what's going on. Did you have an unexpected incident and not make it to the post office in time? Let the other person know. Most people will be understanding as long as there is honest and timely communication.
Above all, listen to your instincts. If the person is being too pushy or you aren't comfortable with the terms of the trade, simply thank the person and move on.