Apologies to the OP for suspecting you for being a troll.
Your credit score will not improve overnight; if it is bad, it can take several years to recover.
My advice stands, read Dave Ramsey's books, or if you don't like him, try Mary Hunt; there are several other good authors out there was well.
As for canceling the cards, some companies will automatically cancel them if you don't use the card for a long period of time but in other cases yes, you need to call and cancel them.
As Russ points out, canceling them all now will result in a drop in your credit score. On the other hand, if it's that bad already, how much does another drop matter, especially if the end goal is to get out of debt and never get in debt again?