Calisthenics is kind of lame. You are training endurance, but most people don't recognize that as valid. From my meme understanding you want to gain higher overall fiber volume by stressing the muscles to maximum recruitment and then letting them rest. So in my opinion, shouldn't you just do some heavy lifts to maximize the recruitment and allow your body to gain mass volume first? This was what a fit-tard told me one day although he was a mentzer type waxing about overtraining and such.
Anyways. The routine I know of for getting to 100 pushups is straightforward and comes from an army trainer with considerable experience. You always do your target total of 100 (or more), and try to accomplish it in the least number of intervals or as fast as possible. So you might start out like 30, 20, 18, 15, 10, 7 reps per set and then get it down to 30,30,30,10 and so on. People looking to maximize their gains usually suggest at least 5 sets of any exercise to maximize activation, although some argue if you really stress your muscles to exhaustion in the first few sets you can ignore the rest. I think the 5 set model is for maximal testosterone activation.
Generally speaking, It's all about ideal protein intake, ideal caloric intake, ideal rest, and ideal testosterone/GH production. The protein levels you will need are quite high, your caloric intake will also be massive. Those two things screw over many people who start. Raising test is fairly easy since you will be lifting, but