Merlinn
My Advice would be not to waste your money on DVD's etc unless there is a particular aspect you are stuck with.
You can't go wrong with the Trevor Thom manuals, they will tell you all you need to know to easily pass the exams and each volume covers a different area, get them all.
Also if you haven't already done so get the manual for the airplane you are flying, apart from telling you the correct speeds there is other information there that will be useful.
You will also find a wealth of information about general safety etc on the CAA web site.
Lastly make sure you start as you mean to go on and that is to know the reason behind the answers to exam questions. Sounds obvious but you will only be cheating yourself in the long run if you don't.
Hope I haven't stated the bleeding obvious but it really is that straight forward.
Good luck and enjoy.