As others have alluded to above, a Master's Study can mean a lot of different things depending on what you want to get out of it. My own personal Master Studies are about trying to copy as closely as possible, and learning what I can through that process. But as @TessaW said above, exact replication can sometimes lull a person into not thinking about what they're doing, so try to make the experience an "active learning" endeavor instead of passive--sometimes that means looking for specific things which can help make the process of creating the study be less overwhelming. I suggest you frame your approach to Master Studies by narrowing the purpose for which your studying it: Direct copy? Values? Technique? Textures? Colors? Composition? Line weight? Edges? Etc. Conversely, it can be daunting to dive in head first and try to replicate everything all at once but sometimes that a good learning experience as well. For my own digital copies, I learned not so much how the illustrator did their work but how to use the tools at my disposal to replicate their pieces. That helped me learn more about what my tools could and couldn't do, and where my own skills were in relation to what they did. It enabled me to see how I could use my digital tools in a way I hadn't thought about before, as well as think about how the illustrators used the various elements of design (line, color, texture, shape/form, etc) to achieve what they got. It was a useful process for me, personally. But I also think that I will approach Master studies/copies in the future with a bit more internal focus. Stating exactly what it is that you are looking for and then being able to articulate exactly what you are discovering as you go along could be a good way of making the experience work for you over and above just a simply copying.