[Q] installing a custom rom topic

I installed cyanogenmod on my HTC One X+. It's really slow now, so I would like to install another ROM. I tried installing another ROM but it gets stuck on the booting screen everytime. I just installed my backup again, so my phone does work again. How do I install another ROM? I figured out I need to flash another image or something. I can't find a good tutorial on how to do this for a specific ROM and with updated files, because I understood from various forums that I need a newer image if I want to install another ROM?

Thank you.