Here's the typical advice on studying martial arts on one's own. Unfortunately for its proponents, I succeeded in doing just this and therefore serve as an example showing that it is indeed possible when you apply yourself, thinking the problems through carefully and designing you routines according to careful research consistent with your experience.
"Why it won't work
Martial arts are highly skill-oriented and require significant feedback from an instructor, as well as copious amounts of sparring (either with striking, such as boxing and Muay Thai, or with wrestling, such as judo, Brazilian jiu-jitsu or wrestling). "Learning" a martial art without those two key components is almost always a fruitless endeavor.
There are scenarios where people already skilled in one combat sport are able to successfully learn techniques from another, similar art. A commonly used example is mixed martial arts fighter Evan Tanner, who taught himself Brazilian jiu-jitsu submissions from the tapes produced by Rorion Gracie. Tanner succeeded in large part because he had a background in wrestling and he was able to practice the moves with resisting partners at home.
Trying to learn techniques at home, without an instructor, without sparring partners, and with training material of unknown quality, is a tough path even for people with some amount of training under their belts. It's unlikely that you'll be very productive starting as an untrained person."
I admit I had about two years training in various schools prior to designing my own program, but I think only one would be required for the serious student.
I recently had a confirmation of my success in the form of an attack by a guard dog and his buddy. I had not trained in over ten years other than my regular visits to Planet Fitness for the previous three years. One morning at about 3:30 when I was walking to Planet fitness for a workout, the guard dog from an auto body shop and a friend of his rushed me suddenly from the front, aiming for the ankles to take me down. The first thought that popped into my head was, oh God, I'm going to the hospital. Without thinking about it, I dropped into an open side stance facing the guard dog, who was coming in faster than the other, and when he was close enough, again without thinking at all, my right foot executed a near perfect outside crescent to his ear. He didn't make any noise, but immediately backed down and sat down about ten feet from me facing to the side with his ears pinned back. His buddy lost his confidence as well and backed up, allowing me to pass. Dogs' ears are sensitive, but again nothing conscious happened before the kick. It was the minimum force needed to stop him and did no permanent damage. He also showed respect every time I walked by that auto body shop after that, sitting quietly with his ears pinned back rather then barking, as he usually did.
How did I develop this skill?
A while back I left the traditional school(s) I had studied at and designed my own workout program, which I practised full throttle for three years, when unfortunate circumstances prevented further progress. My independent progress was impressive, and is due to my insight that energy in physics is the same thing as work, so why is life energy (Ki, Chi, ...), and therefore its development and growth through martial arts, not measurable? I developed a system of points (units of work or energy), one point for so many correct repetitions of a technique, exercise, or form, and used it to pace myself so that I could practice with maximum frequency and effort without burning myself out before the end of the work week. One result was that I was up to training about fifteen hours per week in the third year.
Complex skills are always built from simpler ones, so I cycled through all of my technique practice from the simplest, basic strikes and blocks, through combinations, drills, techniques, and then finally forms. Each time I finished the progression through the complexity scale I started over at the foundation. Of course actual striking practice is essential, and I did a lot of controlled light contact full speed practice against walls and concrete pillars.
The first principle, which more generally is expressible as "work is
life", applies to any exercise program. The second, skill complexity
progression, applies to any martial art system, sport or trade. It worked beautifully, and now I'm ramping up my practice with some design overhaul to enter MMA competition in spite of my age.
Wish me luck.