Martial arts and sport combatives are all pretty much the same in the sense that long term commitment leads to long term success; yes, the degrees vary, because individual response is subjective, but successes can be measured for even the most challenged practitioner. It's all about grading on a curve at that point.
I want to focus a little more on hacking your personal performance or that of your students than I do the gradations of achievement. This is a quick overview of some guidelines for overall improvement that work well in a limited time-frame, whether you're a coach doing the delivery or an athlete trying to find higher ground, but can also inform a longer timeline of dedication.
We can accomplish that by looking at the low hanging fruit of martial training--things that seem obvious, but once you acknowledge them, they become essential touchstones in your skills development. You increase the quality of your training, if not the scope, and this is a good thing; it makes your training less of a mathematical problem ("I don't have enough time. I don't have enough speed. I don't have enough strength.") and more of a computational one ("How can I combine the time, speed, and strength I do have to be more effective?").
It's a bit of a variation on the Albert Einstein quote, "Try not to become a man of success but rather try to become a man of value." Let's improve the value of your training and, if we do that, success will come.
1. Skill First
This is key. Skill training has to take precedence or what have you got? Not much. But once the skill is introduced, start looking for limiters to execution and attack those with a focus that borders on obsession. Skill development is difficult enough for most people, but if there are physical literacy issues too...well, it is going to make it all the more difficult to build the motor patterns necessary to improve.
2. Identify Limiters
Where are things going wrong? This takes a broad perspective on the part of the trainee or trainer, because we are looking for, again, the low hanging fruit. Too often, people ignore these because they seem so obvious. Don't. These aren't always deal breakers in the long term, but addressing them early and often can make a dramatic improvement in clutch moments. This list is myriad, so I'm not even going to try--it could be anything from the music being too loud in your boxing class to wearing the wrong size gi in rolling. You might chuckle at first, but if you're into Brahms and DMX is all "up in here" while you're learning a seven punch combination, you're going to struggle. Address it and see improvements.
3. Conditioning Elements Specific to Skill Execution, but Respect the Skill First
I have nothing against long slow distance training or HIIT for fitness gains, but nothing beats Specific Physical Preparedness (SPP) as a means of achieving the quickest positive results in the shortest possible time. The problem here is physical preparedness is a continuum that slides from General Physical Preparedness (GPP) to SPP, and there are subtle distinctions along the way that only seem obvious when you view it in a macro sense. Burpees seem like a great way to improve capacity for wrestling, say, but the best burpee'er in your class is not always the best wrestler. That's instructive.
I maintain that if you did nothing else but your skill training at varying levels of intensity, you honestly would not need any other conditioning elements. True story. The problem is twofold, though, and they are inextricably linked: coaches and athletes struggle to regulate intensities beyond labeling one class "hard" and another class "easy," and usually those are the sparring classes. Not helpful. Training load is probably the number one determiner of injury risk, but training intensity has to be a close number two and that's an issue to be rectified.
But using SPP as a filter for performance, it becomes apparent that if GPP is helpful, SPP is vital--and how you create SPP opportunities is just as vital. "Shark Tank" drills are more valuable than calisthenics, even equalizing for load and intensity, but only if there are teachable moments included. If there are, it accelerates learning in exactly the medium that will allow a transfer of skill to take place.
Think about it this way, you have two athletes and one does burpees every other day for 30 days while the other does round-robin sparring every other day for the same length of time. All factors are equal for effort and recovery. Who wins when they fight each other on day 31?
The answer to that question is why we keep conditioning protocols specific to skills training if we are trying to achieve success in the most efficient way possible.
4. Offer Lateral or Regressed Options When Movements Are Compromised.
Never underestimate the value of a good coach or mentor. If someone has an eye for detail, they are worth their weight in creatine. (Sorry, that was forced--but you really should be taking creatine if you're not and that was an easy reminder.) The ability to scale movement intensity, regress a complex motor pattern, or offer a lateral alternative are things that can be developed, but some people have a natural ability for it. Having one of them in your life can make your training so much more productive, assuming you listen to them. But if you're not listening, that makes me wonder why you're training with them...? Better square that away before worrying about all this other stuff.
Coaches who are able to take movements and dissect them in a way that builds quality patterns of execution will make any martial journey attainable.
5. Never Load a Motion Against the Pattern
The best example I can think of for this is punching with weights. It seems like an intuitively good thing to do, but how do punches work? Decelerating load that is exerting force in a downward manner through the range of motion relative to the striker's body alignment isn't it. It creates a faulty movement pattern, and martial artists live and die on precise patterns of movement. Consider that when you're attaching load to yourself or your students.
6. Assess and Improve
Everyone wants to improve, but assessment is a difficult concept to grasp and execute. In the absence of all other options--a coach, a mentor, solid training partners--use video. Your phone probably has video and there are a few really great apps out there you can get for (almost) free to improve upon whatever you have. Video will force you to get over yourself in ways that feedback from another person can't even accomplish--you will very quickly get out of your own way if you start watching video of yourself executing skills and, bonus, if you have a trained eye assisting you with the video, you are in an even better place to making improvements.