As you devote yourself to studying art in a serious, continuous way, you will notice a curious phenomenon. After the initial learning curve, you will find yourself coasting for a long time without noticeably improving, no matter how much work you do. You may even feel you're sliding back. This can be discouraging, frustrating, even depressing, but keep going and you'll find that suddenly - sometimes even overnight - your skills will bump up to the next level. It's weird, but I know I'm not the only one this happens to, because the phenomenon was described to me by my animation teacher, so there are at least two people in the world who follow this pattern, and there might be more ... At any rate, it has served as a consolation to me when I find myself on the downward slope, to know that a jump to the next level is just around the corner, according to the natural course of things.
It is also important to keep in mind that as you progress, the jumps become less dramatic - you go from forging a foundation to honing smaller facets of your skills set, so the improvements are less earth-shattering. Even though the slope might not be so steep, though, it does continue gradually upwards, it just takes longer ...