I used to be obsessed with muscle development and how best to go about building muscle. Nowadays I just maintain a good level of calisthenic fitness.
Building
The best method for growth is nucleus overload. Prioritizing proliferation of satellite cells within the muscle. High reps high volume training everyday with long two week breaks.
Pick an exercise or body part, crush it for 3 weeks, take two weeks off. Repeat.
Maintaining
A Daily calisthenic routine is sufficient to maintain a good looking capable natural physique.
Diet
Sufficient carbs are needed to spare protein. Carbs fuel brain as top priority, body second.
You can grow muscle with McDougall starch based low fat vegan diet provided you consume enough calories of starch, eat enough starch to prevent your protein from being converted to energy. Eat low fat to maximize blood flow.
McDougall diet is 80-10-10 carbs protein fat.