Does anyone know the best way to place fondant letters onto a cake?  At the moment I make the letters, let them dry and place them on the cake the best I can. However the letters are very delicate and some do break  Anyone got any tips?

Have you tried tweezers? Works for me!

i put them on pretty much right away. I also roll them pretty thin.

There is really no need to let them dry.  I usually put mine on almost immediately.