I don`t think there is a "proper" way of practacing. What works for me might not work for you. It depends what you are looking to get out of it.
Do you want to be technically proficent? Do you want to play with a band doing a particular type of music-eg Jazz?
Me, if I`m going for an audition, I`ll learn the material or just work out songs that i like to play. I try and play every day even for 20 mins or so. Sometimes I think I`m decent and other times I just can`t get it together.
I can`t be bothered learning all the triads, scales, etc. But that is just me