Evaluate Yourself Honestly, but Stay Positive
Studying music and practicing hard does not come without periods of frustration. You will have weeks where you're quite impressed with yourself for the obvious progress you're making. Then there will be those periods of time — even long periods of time — where you feel like you're making absolutely no progress at all. That's because you've reached a plateau.
Topographically speaking, a plateau is a large stretch of flat land raised sharply on at least one side above adjacent land. Plainly speaking, this means you've just completed a steep ascent and now you're in for a long stretch of level walking. And musically speaking, this means you've made a large leap forward in your technique, but now your brain and your muscles have been overloaded with new information and need time to absorb it before taking more on.
The fact is, you won't see obvious improvement every single day that you practice, and there will be long stretches of time when you wonder what the bleep your efforts are producing, since nothing seems to be changing about your playing. Be assured that there is light at the end of this tunnel. You'll wake up one morning and be able to play a riff that's been eluding you, just like magic. It's the interest on your deposit.
Your brain will always be ahead of your technique. This is true even for the greatest musicians. The unattainable goal is to be able to play anything your brain can conceive with perfect technical execution. And the fact that this is unattainable is a good thing — it means you'll always have something to strive for!
That's the challenge that drives you forward and ensures that practicing will never be a waste of your time.