1. nand backup of current working rom to have something to go back to if necessary. Be good to have your apps up to date and use titanium backup pro to copy them. Use whatever prog you have to copy any texts or mms you might value, as well.
Use an app like appsaver to put tb and tbpro key on your sd card. Make sure you battery has a decent charge too.
2. Check out our Roms and Kernels thread to find a replacement. Go to the developers thread and read about it, what features it has, themeability, mods, what doesn't work, etc.
3. Dl it to pc
4. Boot into recovery and use Usb cable, turn on USB-MS toggle
5. Put the new rom on the root of sd card, i usually drag and drop it right on to the drive.
6. Get out of usb-ms toggle
7. click down to Wipe menu, at minimum wipe Cache, Dalvik Cache and Data 3 times a piece. Some suggest everything but SD card. For sure wipe sd-ext if you are partitioned and have been using a2sd.
8. Click to Flash zip menu and select to flash Superwipe zip
9. In Flash zip menu, again, select your new rom to flash and do so.
10. Put your phone down and leave it alone for awhile, patiently waiting for it to do its thang.
11. After a decent interval to let phone gather it's wits, do the phone setup thing.
12. Use whatever filemanager app rom comes with to locate appsaver folder and install tb and tbpro key
13. Restore your apps, or apps and data, but no system stuff in red writing.
14. Place apps as desired on screens, mod theme, personalize to taste!
I am sure I have probably missed something but if I did, someone will pop inn and correct me.
As usual, only stupid question is one you don't ask!