Glad to see you got your phone working again.
Seems like you did successfully root your phone the first time even though you were having slight issues with it afterwards.
There really is no one good place to look to learn everything about rooting. The best way to learn about rooting is to hang around these forums(there are a couple other good forums too) for a couple weeks and read the threads that people post, especially the ones where people are having problems. Then you can learn what to do when you encounter a problem and not freak out when something happens (kind of like what happened to you).
The first issue you are going to run into since you are new Incredible owner is the fact that you have an SLCD screen vs an AMOLED screen that the original Incredibles have. The SLCD screen is currently not supported by the official ClockworkMod recovery that is loaded onto your phone by default when using the UnrEVOked rooting tool. So the first step you need to take after rooting your phone is to flash the modified clockwork recovery available on Adrynylne's website.
You would flash that file in hboot by renaming the file to PB31IMG.zip and putting it on the root of your sdcard, and then boot into Hboot by turning off the phone, then hold down the volume down button and press and hold power until you see the hboot menu, then follow the on-screen instructions.
Your next step is to boot into recovery and make a backup of your phone...
As to your question about increasing battery life, besides just tweaking settings on your phone, such as turning off wi-fi and bluetooth when not use, and using wi-fi instead of 3g for data when possible. The best way is to download a custom kernel that you can underclock with set-cpu.
Info on kernels can be found here
Incredible Kernel's: The What, Where, and Why. Updated 08/11/10 New Froyo. 32 Kernels!
Kernels can be a trial and error type thing as to what works for you.
But anyway that's enough info for now. I'd also recommend looking at the stickied thread at the top of this forum for information.