First I suggest you install Amon RA v2.3 recovery available at
[Recovery] [09-Feb-2011] RA-supersonic-v2.3 - xda-developers. Download the file PC36IMG.zip to your computer, copy the file to the root folder of the EVO's SD card, power the phone down, press and hold the volume down and power buttons simultaneously to access the bootloader. Once the bootloader starts it should detect PC36IMG.zip and ask if you want to update the bootloader; select yes and Amon RA recovery will be installed.
The ROM I currently use is MikG 3.11 available at
MikG v3.11 [3/9/2012]. Be sure to download the full version to your computer. I also use the Classic Sense Kernel v 1.5 available at
[KERNEL][WIP] Classic Sense Kernel v1.5 [JUL 22 2012][GINGERBREAD][SENSE] - xda-developers. Be sure to download the SBC version of the kernel for improved battery charging.
After you finish downloading the zip files for the ROM and kernel to your computer, copy these files to the root folder of the EVO's SD card. Review the youtube video at
How to Flash a ROM on the HTC Evo 4G.flv - YouTube to get an overview of the procedure to flash a new ROM on your EVO. Make sure the EVO battery is charged at least 40% before trying to flash the ROM.
When you are ready to flash the ROM, power the phone down then press and hold the volume down and power buttons until the phone boots into recovery. Use the volume up/down button to highlight Recovery and press the power button to select. Before flashing a new ROM you should perform a nandroid backup in case you need to restore your current working configuration. To do this select Backup/Restore and press the power button, select Nandroid backup and press the power button, select Perform backup and press the power button, then press the the power button to confirm that you want to perform the operation. The nandroid backup will take up to 10 minutes to complete.
After the nandroid backup is complete, select Return, press the power button, select Wipe, and press the power button. Now select Wipe CACHE, press the power button, press the power button again to confirm, select Wipe DALVIK-CACHE, press the power button, press the power button again to confirm, select Wipe DATA, press the power button, and press the power button again to confirm. Now repeat Wipe CACHE, Wipe DALVIK-CACHE, and Wipe DATA. Next select Return, press the power button, select Flash zip from sd card, press the power button, select Choose zip from sd card, press the power button, use the volume up key to select MikG-v3.11-signed.zip, press the power button, press the power button again to confirm, and wait while the ROM is flashed. Do not power off your phone! After the ROM flash has completed, select Choose zip from sd card, press the power button, use the volume up key to select classickernelv15-sbc.zip, press the power button, press the power button again to confirm, and wait while the kernel is flashed. After the kernel flash has completed, select Return, press the power button, select Reboot, and press the power button.
The first boot after flashing the ROM will take 10 minutes or so. After the phone has booted, you will need to configure your gmail account and reinstall your apps from the Play Store.