Something I came to realize was that being a good instructor is something that a lot of people who own schools are not doing. Regardless of how skilled they are, or their accomplishments, teaching is a whole different ballgame.
Teaching random techniques daily, and then telling the students to wing it is NOT good instruction. The people who succeed under this type of instruction have done so in spite of the instruction. They may or may not understand how to continually improve efficiently by themselves.
The most important thing to understand in my opinion, is having context to the material being taught. Simply put, there is a curriculum that I've come to understand that provides the most efficient learning for students. I didn't arbitrarily pick the order btw, it is strictly from analyzing my own progress and struggles from day one, as well as comparing the students who advanced quicker to those who didn't, side by side.
It starts with the worst case scenario (which is also 90%+ of the reason why new people lose) to progressively learning the next logical part of the game.
1) Escapes (from every single damn position). The goal here is to cover how to get to the half guard from every position. Why half guard? Because in terms of worst case scenario, half guard is the next best thing, one notch above being in the positions where your guard is passed. The vast majority of white belts lose their matches NOT because they don't know the latest submission or rubber guard, but because they absolutely suck at escaping. Preventing guard passes also falls under this category. I feel that every single white belt who just starts out should focus a tremendous amount (an absolute metric shit ton) of time simply on escapes and not getting your half guard passed.
2) Sweeps - Once the escapes are mastered, typically the next thing is to learn to get on top of the opponent. Sweeps starting from half guard, then open guard/butterfly/different variants and finally full guard should be learned. It is at this stage that most people receive their blue belts. Because escaping is no longer a big problem, the focus should shift to the sweeps. There should be no bullshit about working on the latest submission, or practicing the newest guard pass quite yet. Yes it is good to learn something from every position, however 90% of the focus in training should be devoted to becoming a THREAT from different forms of guard.
3) Guard passing/Takedowns - Once the sweeping is solid, against most people of the same rank, getting on top should not be a problem anymore. The sweeps should be so good, that you are threatening nearly everyone you roll with to some degree. At this point, technical guard passing should be developed. It is very likely that in a tournament (assuming the person has reached this point), the most likely cause of a loss is not being able to score a takedown, or not being able to pass the guard. And yes, good guard passing implies that you also are working on NOT getting swept. Having the right pressure from the top is a fine art, and developing this along with takedowns will increase the amount of matches won far more than learning anything else at this point.
4) Maintaining the good position/transitions - This is also a point that is sort of neglected in training. The highest level competitors have the best/quickest transitions between one good position to another. So to succeed in a tournament, you want to try to emulate that. i.e. taking the person's back quicker than they can turtle as they defend a guard pass. Typically as the opponents get better and better in tournaments, quick transitions and solid ability to maintain good positions will make or break the matches.
5) Submissions - Finally, submissions. Not that the person shouldn't invest ANY time until now on submissions, but the focus should be somewhat basic until here. Submissions from EVERY position should be practiced. Assuming all of the above have been mastered, having excellent subs from everywhere will complete the game plan, and I am pretty sure from my experience that once this is achieved, the black belt level has also been achieved. The ability to finish matches and really punish the opponent for making a mistake, or not being able to impose his own game really separates the elite black belt competitor from the not as skilled competitors.
So, this isn't the end-all be all way obviously, but at least from my point of view this has been more or less the most accurate picture of the fastest way to improve in bjj.
Finally, one more point I would like to mention is
Big guy game vs little guy game
Being a somewhat little guy myself, there have been plenty of times where I lost to someone bigger who had far less mat time than me. Yes it was frustrating, but over the last 6+ years, I learned a REALLY valuable lesson, which is that: there are two different types of game plans that everyone should learn.
Yes. One for the people who are bigger than you, and one for the people who are the same size or smaller.
The absolute PERFECT example of someone who plays the way he should against a bigger opponent is marcelo garcia.
The main point in this game plan for bigger people, is that when you are on bottom, you strictly limit the moves you do to the ones that do not let the bigger guy put any weight directly on top of you. This means, no normal half guard, no deep underhook, no flat on the back. There MUST be something framing the top guy (your forearm on his neck, your foot on his hip, your butterfly hook, ANYTHING) but the weight must be off. The attacks have to come very aggressively via arm drag, single leg, head lock/snap down, taking the back, leg lock, or standing back up.
big guys who are equally as skilled as you, will most likely beat you. So the point is to be so skilled at this game, that being matched in skill is not possible.
Now against people your own weight, the above game plan plus all of the rest of the moves can be used with no consequence. The worst thing is when I see someone trying to use the same game plan against everybody, and it includes the big guy putting weight right on top of the little guy. This indicates a severe lack of experience.