Dude, just practice. It'll take a very long time. There will always be matches you will lose, no matter how good you are. The most important thing to take out of it is why you lost, and to learn something. All in all, if you practice diligently, you WILL get better. But it will take time and you may not realize you're improving. You can't rush the process and sometimes it can be overwhelming and disheartening. But you definitely will keep improving as long as you try. The only way to fail is by giving up.
I actually have this exact same thing. Unless I do it in a match once, I cannot get used to it. Training mode is useless for that.