Embody Your Goals:
I'm not a very confident person. Or at least that's what everybody tells me. I prefer to think I am just being realistic about my abilities. Okay, yeah, I'm just plain pessimistic. But putting that aside, the advice I hear the most in my life is this: “Fake it 'til you make it.” While I may not have applied this idea to my self-confidence, I've realized that I did use it to learn Japanese. Seeing as “Fake it 'til you make it,” has been spewed at me by well-intentioned-but-nevertheless-annoying people all my life, I would really prefer that I not use it myself, so I'll instead say this – Embody Your Goals.
What does that mean? That means acting as though you have already succeeded at what you are setting out to do. In the case of learning Japanese, it means using Japanese as though you were a native speaker. You want to watch TV? You watch it in Japanese, because you are Japanese. You want to listen to music? You listen to Japanese music, because you are Japanese. You want to read a book? You read it in Japanese, because you are Japanese. Of course, the goal with learning Japanese is to learn the language, not literally become a Japanese person, but it's about the same in effect.
You're probably thinking, “But that sounds horrible! I'll be one of those posers that pretends to know all about something, when really they know nothing! I'll be the guy that can't draw that carries around a sketchpad! The clueless amateur photographer that carries around a huge bag of lenses! That one guy that carries around a guitar!”
I won't lie. You will be that. It's pretty embarrassing.
But the thing is – eventually you stop being a poser. If you pretend for long enough – if you embody your goal for long enough – eventually you BECOME what you set out to be. At some point those posers actually become what they pretend to be, but then you don't notice them – they just look like artists, photographers, fluent Japanese speakers, whatever. Your mind points out the posers and fools you into thinking they don't succeed (granted, some don't), but it has no way to notice the ones that DO succeed!
The best way to become good at something is just to do it. The only way to get better at drawing is to draw. The only way to get better at playing an instrument is to play it. That is what “posers” are doing when you see them carrying things around – they are being prepared to make use of every spare moment to improve. That is how you should approach learning Japanese if you really want to master it. Every spare moment should be filled with Japanese. Reading manga, going over Anki reps, watching random Japanese videos, anything and everything.
I could go on, but I think you get the idea. Become your goal.
Live it.
Breathe it.
Keep it close to your heart and ever-present in your mind.
You are your goal.
The secondary message here is this: Forget about everyone else. People will doubt you. People will tell you that it can't be done (with their eyes, if not with their mouth). These people are only right if you listen to them. They don't matter. Stick to your goal and one day you'll face those same people again – only now they'll be amazed at what you can do.