There's no wrong time, or wrong way to study masters! Many artists (myself included) got started doing copies of comic and manga artists they admire. The only way you'll start to pick up on the techniques used by artists you admire is to try to reverse engineer them yourself! You don't need anything other than your current skillset to jump into a master study. Each study you dive into will help you grow as an artist. Just be open to the learning process, studying masters is difficult!! It helps to have a reason you're approaching a particular master study before you begin, so you can maximize the takeaway from a particular study. Working on gesture? Try to draw some gestures from Yusuke Murata, and then draw some gestures from Tite Kubo's work. Then compare the two, notice similarities, differences, etc. The point of a master study is not just to replicate a piece exactly. It's to begin figuring out your process of how to complete a picture using what you know of drawing fundamentals. Try not to think about drawing the finished piece as you see it. Start with studying the gestures, poses, or portraits you see in your favorite Manga. Do thumbnails, do quick sketches to figure out the poses, try to exaggerate them, push them, play and experiment with them. Have fun! If you start to get close to a gesture you really like, take it to the next step, try to add structure and form on top to give the gestures depth. You're just trying to build the piece step by step using your current knowledge and skill set. You don't need to take it all the way to finished each time. You can work up to that as you start to develop your own process, one element at a time, until you're comfortable taking it to the next stage. It helps to do some research to find out how a particular artist works, what materials, or techniques they use in the process, etc. But you don't need to adhere to their exact methods or materials. You could easily do a graphite study of an inked piece, and try to replicate the look as best you can in pencil. Also vary your master studies! If you like how one artists draws characters and how another artist draws vehicles or environments, study both! Don't focus on trying to "find a style." Focus on executing what you know, and what you can do in the moment. That's all an artist's "style" really is. The more you practice, the more it will develop over time. Whatever you choose to study will start to become part of how you draw, and your style will evolve and emerge with each study you do. Hope this helps! Looking forward to seeing your studies!