Q: Moving to El Capitan from snow leopard (10.6.8)

Hello

Reluctantly, I recognize that I have to move on from Snow Leopard, and want to do so before Sierra comes out, and I know that I've procrastinated and time's running short.

System configuration as follows:

Model Name:    iMac

  Model Identifier:    iMac11,2

  Processor Name:    Intel Core i3

  Processor Speed:    3.06 GHz

  Number Of Processors:    1

  Total Number Of Cores:    2

  L2 Cache (per core):    256 KB

  L3 Cache:    4 MB

  Memory:    12 GB

I have time machine for backup, and also a second bootable backup on CarbonCopy clone (which I only connect weekly to backup).  I also use Carbonite for an on-line backup.

I know that some programs will not work (most critically Office 2004).

What other steps should I take before installing El Capitan, what problems can I anticipate, and what do you suggest for the most painless way of doing this?

Thanks in advance.

Dan