i find its hard to sell players in FM2011, and i figure out some ways to sell them,:
-loan them , send them to loan, let them have fitness, games experience, then offer to all clubs.
-find feeder club, find a good one, and send your players to that club, let them play few month and offer to clubs.
-make exchange player, if you buy one players, trade it with your players, but make sure they want to buy player in that position.
-its better to get something than nothing, sell your players with 30-50% discount!!
-last but not least, try to play them wherenever possible, rotate your player, by doing this, it could help them to gain fitness, show other clubs what they can offer..
gudluck selling players!!