Hey mate.
When I started, i never got discouraged actually. But frustrated. Frustrated because i didnt get results, frustrated because i knew that i was my biggest cockblocker. But i never got discouraged. There was always the thrill of going out. What is going to happen this night? Who am i going to run into? That was encouraging enough. Also, seeing those hot chicks... darn. I was going to get better. I spent all my free time and it still was the most exciting time in my life.
I pushed myself into changing after a very bad relationship. Since then, my game was triple as good as it was before. Which encouraged me even more.
Also, i just enjoyed the freedom i had. I knew i just could do everything i felt like. And i wanted this badly, so i put all i had into it. With hearth and soul,the full monty sort of speak.
And that is what you should remember from time to time:
you cant make anybody else happy if you cant make yourself happy. So reflect for an instance and think about what would make you happy. Then go do that every once and a while. For me, i was lucky. I really really wanted to master this, asap. And i enjoyed every bit of it, frustrated or not

.
cheer up mate. Most of the time, when you feel like you arent improving anymore, its self reflect time. Be honest with yourself and you rapidly find your real problem. Its mostly fear for that one step to success, which is expressing how you feel about the woman. Is it either verbally or by kino escalating, most of the time, fear for doing it is the real problem. And there is no book on this world that can show you how to conquer yourself. You need to do that by yourself.
good luck!