From: Cross Lanes WV USA
The AI is pretty canny at trades, but I've found that the bait and switch can work.
Here's what you do: you dangle a high-value superstar to a particular team, and see what they offer. When the list pops up, then switch your offer to a lesser player. The AI will make a counteroffer.
Another tactic is to offer up an expendable player to several teams, to test the counteroffers.
Yet another is to split up deals with a particular team. A 2 for 2 might not be accepted, but separate 1 for 1 trades might work.
To me, it's not cheating the AI. However, a definite house rule is player-for-player trades, i.e., no 2 for 1 or 3 for 2 stuff. THAT, IMHO, is cheating the AI.
To sum up, practicing in the art of negotiation pays off.