First off, make sure that you always make a backup of what you have working on the tablet. This will save you much frustration if something goes wrong. Nandroid backups are the ones that will restore a whole ROM for you. As for backing up apps with data, you can use Titanium Backup (requires root).
The two main firsts are that you should get it rooted (very easy now) and install CWM (Clockwork Recovery Mod). CWM will allow you to flash ROMs, make backups of the ROM itself and handle various memory functions.
Read through the Stickies in the Android Dev section, they will tell you all information you need to know.
As mentioned above, if you run into any kind of issue, before you post, use the search function and see if it is something that has been asked and answered before. If you are following the steps to whatever you are doing and you get stuck, chances are good someone else has done the same thing and gotten help with it.
Another thing to note is when you choose a ROM, look through its feature list, and if available, the bug list. Looking through both of those should aid you in deciding if that specific ROM or Kernel is something you want to use. If you get as far as flashing Kernels, make sure it is one that is compatible with the ROM you are using, otherwise the tablet probably won't boot and you'll have to flash a Kernel known to work with whichever ROM you chose.