The term this page uses for those "lessons" you mention is practice goals. There is even a button on this site. that asks you to select a practice goal from a multiple choice selection, and if you didn't change it for four weeks, you get a reminder. But that is only a minimal crutch, and after you get more experience with different approaches to drawing, these selections start to feel incredibly vague. There is the option to type in your own words, though.
Ideally you should select a specific practice goal for each of your drawing sessions, and try to put it into your own words and/or visualize the effect you are going for. Those different tutorials offered you different tools for your toolbox, now it's up to you to learn to distinguish between them, and to select and chose consciously which specific tool fits your artistic vision best. In a faraway future, when we approach the horizon of mastery, we probably want all of this tools at our disposal.
And I know, that sounds all great and almighty, like I figured that all out, and I absolutely haven't. Compared to a lot of other draftspersons I lack discipline and tend to just wing it a lot more often than is good for my artistic development, but having given a lot of feedback to other artists here, I at least have seen it done right by some people, and occassionally I succeed in getting it right myself.
I think (I hope) becoming aware of the general problem, and at least trying to address it by attempting to become clearer about my goal for every session, before I just start scribbling away, is a step into the right direction. On the upside, trying to define my next practice goal for drawing is an uplifting mental exercise when I am stuck at work, or forced to do boring chores. How successfully I then manage to stick to it when the pen meets the paper is another question.