first of all, I want to know if it's possible to train a six year old dog? He's pretty smart, but takes a while for things to sink in.
I want to teach him some tricks, I tried when he was younger, but he was way too energetic then.
Anyway, so if it IS possible, what are some good tricks to teach him and how do i teach them to him. Also any tips on how to make the process faster, and so I don't do anything wrong.

Thankyou!