Well I'm not about to write a book on Vista, nor would I be able, I'm still learning new things about it every day. I experiment a lot with it.
I can give you a couple of tips that I found the hardest to deal with:
1. Get some imaging software, image your root partition regularly when you first install and are installing new drivers and software. As I said I experiment a lot, I installed quite a few things that totally messed up the system that only reinstalling would fix. It was much easier to go back with images, and more reliable than system restore which is no good if you can't boot.
2. UAC sucks, I have really tried to keep it enabled, but it did not let me install some software and drivers, no matter the settings. It was also way too annoying.
3. Don't over-tweak, I made that mistake way too much, if you turn off some services and functions that seem to use up system resources you will also lose some functionality. Be careful and informed about what you are doing before turning things off. You may think Vista is using too much resources when you see the HDD activity and watch your system monitor, however virtually everything runs at low priority. If you launch an app or a game Vista will stop it's unnecessary processes and give as much system resources as it can to what you are doing in the forefront. I have played around a lot with vLite to try to speed up the system, all I ever achieved was a smaller installation with less functionality, it was never faster. My current installation is virtually default with some performance enhancements turned on, it's just as fast, and works better.
Check out
this guide for a lot of basic info about Vista, it's quite good to get you started with Vista.