I am sure there are many short cuts and quick ways to do thing, here are a couple I discovered by mistake only Today. I am sure some people will say "I already knew that" but some of you might find it useful.
On the message menu you can slide the contact off the screen to the left to send a message or you can slide the contact off the screen to the right to instantly call them. This can also be achieved from within the contacts menu.
Please post any shortcuts you have discovered.