Practice

There is exactly one way to get good at something: Consistent, focused, self-critical practice over a long period of time.

What I mean by this is simple.

You must do it consistently, that is, no 3 month breaks, followed by a few mad weeks, followed by another 1 month break. It just doesn't work for most skills, and especially skills that require a a base-level of endurance. After a couple of weeks, you begin to lose your strength and endurance, and so, you ability to do whatever skill you were practicing.

You must be focused; if you're practicing by having ten minutes here, watch a YouTube video, 5 minutes there, watch some TV, etc. You'll eventually find your practice sessions simply not amounting to much more than watching TV while doing something that's only ornamental. You'll also fail to pay attention to what you're doing, and as a result, simply not notice if you're making mistakes, or be disinclined to fix them.

I will occasionally listen to a podcast while working out (though I don't recall what they're on at the end), but more commonly, I'll listen to some music.

Self-criticism is a very difficult subject. I personally struggle with this one, even with those far more advanced than me telling me that I'm doing well, I am overly self-critical, tearing myself down. I often note all of my flaws, without taking any real action to fix it.

What you really need to do is acknowledge your achievements so far, but also take on what you're struggling with without guilt and, if you're struggling to advance, ask for help. 

For instance, I was struggling with my left sided standing breakfalling some time ago. I asked a sensei, off the mat, what the common mistakes were. Next time I was on the mat, I took my progression backwards (as in, I went from standing to just-over kneeling), I paid attention to the potential common mistakes, noted which one I was doing, corrected it and continued. I still sometimes make the mistake, but I know the warning signs, and I know to re-attempt, while fixing my problems. That particular mistake is happening less and less.

A common refrain is the 10,000 hours of practice refrain. What's rarely mentioned is that you'll be crap at the beginning. Ensure that you're practicing well, and get over the self-inflicted guilt about your performance. You need the self-confidence to know that one day, you will have improved, and to let that guilt go. Everyone sucks to begin with, and only immature people will judge you for being bad at something when you're starting out.