I will trade same set duplicates in most of the cases.
I can trade cross-set duplicates of similar market value. if the card you offer is of lower value add something to compensate.
In other cases I will only trade cards if I already have badge at maximum level.
I can occassionally agree to trade non dupicated cards if it helps you complete the badge. Add message to the trade in such case.
I will decline the trade if it doesn't follow those rules.
You can get blocked if you don't follow those rules or if I judge that you trade cards for profit and not to create badges.