Criteria for adopting any training method

I’d like to know what criteria you use when deciding whether or not to follow a particular practice method while drawing.
I’m not looking for an authoritative answer; rather, I want to analyze my own situation and choose a practice method that suits me based on my own judgment.
However, due to time constraints and other factors, this is quite difficult.

Hello, 
I think it depends wether you like fast drawing or very precise drawings.

As I like drawing fast and sketching from live, I use most gesture and line of action, but I find sometimes that lacks proportions, so sometimes, I come back to methods teaching proportions of the body. The advantage of sketching in the street or in the metro is that you can do it very often but always in small format.

I don't use many anatomy lessons, I don't like it very much, but sometimes I should too. 
In my drawings, there is almost no shading, just lines, that something I want to learn now, but I'm not sure of the right method for that.

I think you must choose a method corresponding with your style of drawing, then go back to other methods to improve what you are not so good at.

Excuse me, I'm french so my english is not very good.

Thank you for your reply.
This might turn into a bit of a meta discussion, but
I rarely feel confident enough to know whether a particular method will actually help improve my skills before I try it out.
In practice, I feel like I’ve been choosing my practice methods based on the following two criteria:
・Trying things out haphazardly based on heuristics
・Making authoritarian choices
So I was curious to know what criteria other people use to make their choices.

In my country (Japan), partly due to a backlash against the “grit” mentality in recent years,
the mainstream approach is to choose practice methods based on whether they’re “fun to do.”

When I started drawing I actually didn't knew any practice method, I just started copying images I liked, and I maintained myself doing that after realizing I wanted to make things of my own. I never went to an art school, and when my profession didn't had to do anything with drawing, I simply kept drawing from imagination, but I actually got an ability to adapt very fast and learn without putting too much effort. Now, I've encountered with a wall, I want to pursue a career in illustration, my drawings are stiff, I understand the basics, I got some grip from anathomy and color, but is not enough. I like to make what I want, but now I think everything depends on your goals, for me is achieving dinamic drawings and a better color application, not just static poses and random colors, so, based on my objective, I search for practice methods that can help me get there. If the method works or not, that depends on how much progress do you see, this is another thing you have to learn by your own when you are a self-thaught artist, detecting if your drawings are off, but trust me, with time, you actually can see improvement even if there is no one to coach you.