The best advice I can offer to you, honestly, is to immediately drop everything you know about Windows when you sit down to your new Mac. It's not that the experience will be so different since both Mac OS X and Windows are GUI based computers, but they are different and you will need to drop your Windows habits and Windows way of thinking otherwise everything on the Mac will "seem" complicated.
Here's some examples:
On the Mac the Finder is a more simplified version of Windows Explorer. Honestly it makes file browsing and file management much easier but some people coming from Windows want all the complicated Tree View file management and Cut N Paste features from Windows and those will not be in the Finder.
Apple's Safari browser is a awesome browser however one feature that people coming from Windows complain about it they can't click on the zoom button and expect the browser to zoom to full screen, it won't on Safari. Some 3rd party browsers like Firefox will.
Some applications on Mac will not "quit" when you press the close button. On Macs, the application runs in the background while the document shows on the screen so if you just close the document the application still runs, you have to quit it from the menu or a key command on the keyboard. It's much easier this way but people coming from Windows expect it to work the "Windows" way and it doesn't.
These are just some things to expect and if you sit down to your Mac with an open mind and not, "It's gotta work the way Windows does" mentality you will have a much better experience learning your Mac and you will greatly prefer the way it runs and in the end you'll understand that Windows doesn't make much sense the way it runs.
