So I wanna create a shounen-ai, tragedy, yaoi, slice of life, sci-fi BUT-

Okay so I wanted to start a shounen-ai, tragedy, yaoi, slice of life, sci-fi webtoon and there are 2 things that I am stuck on.
1. I want to have a specific style like back to school, I just like the rough art style, mine is to soft http://www.mangago.me/read-manga/back_to_school/?Fvnx , this is the link just in case ya'll wanted a reference there is also angle buddy and royal servant to, I just like that kinda style except theirs doesn't look as rough as theirs.
2. I have no clue how to draw nice muscular men without them looking like they came straight out of Jojo's bizarre adventures. Like I can draw a male, they are either just to feminine, or to musculant.

So any advice on how to change my art style to look more rough and how to draw a guy? A nicely built guy? So, if ya'll could recommend some tip's or some good drawing tutorials for this stuff cuz I can't find any really.... I've watched 12 and I still cant draw a nice boy.... Help....