Ok, to change all verbs in a potential form is very simple. I assume you know about the verbs godan and ichida.
For the verbs godan:
Change the final U of the dictionary form in ERU.
For the verbs ichidan:
Change the final RU of the dictionary form in RARERU.
Fo the irregular:
来るー＞こられる。
するー＞できろ
All verbs so obtained will belong to the ichidan class.
I don't remember who, but someone had told me once that being できる the potential of する, makes no sense the form することができる. However, if you google it, you will get hundreds of milions in return so I guess you can still use that form (even tho I admit it sounds very redundant).
If a native speaker can explain it I would be very grateful
