heck, you might even have to stop thinking in objects and all that comes with OOP because sometimes it just doesn't apply.
A good starting point is this book
it's free and it's a also refresher on computer science in general, download chrome or firefox (with firebug) to help you debug (c'os that's a frustrating task, at times)
As someone mentioned already it's a completely different mindset.
(and yes, JQuery is a must)