Leann Follain flies out anytime we have it on cask. Metalman Pale ale is also very quick to go. Only ones I find we have trouble with are stronger English ales and sometime red ales.
Cask management is very important, make sure the lines are cleaned as bar staff often forget that the breweries won't be out themselves to clean the cask line.
Also important is advertising the cask. Make sure you get pump clips from the breweries(make your own if not) and stick a poster up/chalkboard somewhere very noticeable at the bar advertising what is currently on. Train staff on how to promote the cask, stick a couple of "cheat notes" beside the cask engine that detail what the beer is/what it tastes like. Train the staff to offer the cask beer e.g. someone asks for a pale ale "we've got a nice pale ale from Metalman on cask".
Failure to sell the cask quick enough will result in a downward spiral were the beer starts to deteriorate and regulars stop buying it.