Well this is general knowledge but it always helps. Sorry if someone has already posted something like this. Well as my first serious post here goes:
1) HAVE PATIENCE...never rush into trades! always look at the accounts up for trade and then LOOK AGAIN! if you dont find what your looking for then simply wait. There will soon be an account that is suited to you!
2) BE SAFE... always talk to the seller/trader first and make sure she/he is the original owner or has all the details. Also question the seller/trader. Ask questions like how long have you played and have you ever traded before. Also look at there rep and accounts traded on the forum.
3) MEET UP... So they have offered you an IMBA geared pally, what you have always been looking for, but how do you know it is there's and not some character they have found on the armoury. Well firstly use common sense. Would a 70 IMBA geared pally really want to trade for a 55 rogue? If the trades seem reasonable meet them ingame! I never even look at posts if they have no gametime. This is the only way to make sure they are the real owner!
4) the last think to do is always use a trusted middleman. here is a list of all the middlemen services on wwwwowtrade.org
http://www.********/wt/index.php/board,88.0.html
Look for Middleman with high rep and good feedback. If there are no trusted middlemen online, then wait! there is no point in compromising your account safety due to being impatient!
These easy 4 steps will help you trade easily without hassle. Hope i didnt type too much and thanks for reading