@TianLian I think you're too hard on yourself. I would not call your art dull at all-it's the opposite in fact! and I wish I had half of the inking skills you do.
@Feleri already makes some really great points and like she says, there's no universal answer.
I will say that you're advanced enough in your skills that almost any topic you choose to invest your time in will serve you well. So I wouldn't stress out that you'll be wasting your time. The most important thing is that you give enough attention to your topic of your choice, that you are learning a theory, you are doing drills based on that theory, and you apply it to some kind of finished piece. Don't think you need to learn a certain topic all in one go. As long as you put in good effort to the topic, you can move on to another one, and always come back to a topic again.
You could study 1 to any number of topics at a time, as long as you are putting enough time and attention to each topic. Make sure you are working on that topic several days in one week and make sure you have at least one day to rest your mind. You could work on it 1-3 hours a day for 6 days a week. You could work on it 2 hours every other day. You could work on one topic for 30 minutes a day and another topic for 2 hours on the same day. I don't think the specifics are important, as long as you are getting in enough time to learn the theories and are doing assignments within the week.
It may help to make a list of all the things you want to study. Break down that list into specifics if you need to. It might be enough to put just "values" for one topic. But for anatomy you might break it down further into gesture and the different body systems. Try to put them into a general order of study. Then just start working through the list. Some things like gesture, you might be working on for 15 minutes a day for months at a time. Some things, like hand anatomy, you might work on for a week. Be flexible. You might add things to the list, or take some things away, or change the order, and that's ok. Every once and a while stop to evaluate your schedule and the things you want to learn next. When you've made it through the list, do another one.
I'll make a general suggestion of what to study and in what order.
Work on anatomy every week.
Brush up on some perspective skills.
Move on to black and white light and shadow theory and values.
Move on to some color and light.
After that, who knows? Go back to perspective? Learn about composition? Again be flexible and reevaluate as you go and pick up new skills.
If you start getting uptight or stressed, perhaps give yourself a mantra to tell yourself. My mantra is often: "Relax, have fun, it's not that serious".
Good luck! I hope you find a system that works well for you. I"m excited for you!
