I've only done two trades, and one of them was by 
accident ^^;;.  I say if you have something up 
for trades, just do a mass emailing or posting 
saying "I got this for trade!  Im looking for 
this!"  That works well with me :).  I currently 
have a cel up for trades right now that Im having 
a REAL big problem with though...I did the whole 
mass emailing thing and only one person was 
slightly receptive.  She has a few things I like, 
but I know she likes them too...so Im afraid to 
ask.  What I like to do is ask the person in 
question what in their collection is 100% off 
limits.  Then at least you know what you cant ask 
for, and it saves everyone time.