I want to become a super user

[Dmillertime]

So I have a new phone and now I am left with an old droid pro that I want to use as my test subject. I have never Rooted, overclocked, used custom roms on my device or tried doing anything thing that wasn't the normal with my phone and I would like to try it out now. So where, how and what should I do to start?
I have no problem rooting my phone to old android versions or new ones I just want practice at all this stuff before I toy with my Transformer or my S3.

So what are some cool practice things I can try to.

Thanks