We have a few tips for you to master this problem a little better. It doesn't matter if you want to learn a new instrument, stick to a training schedule, study for exams, or learn to juggle; the tips are applicable to all areas:
You reward yourself
Yeah right, the classic. The thing is, it really works. Set yourself something great to do/eat or whatever once you've completed the task. The important thing here is that you don't weaken and then indulge yourself in the thing beforehand, otherwise you'll have a counterproductive negative experience with it and it will be even harder to stay motivated. A little self-discipline is a must.
Increasing situational interest and personal significance
Let's face it: most things we simply don't do because we have no interest in doing them. I'm sure we've all been in that situation where we've thought to ourselves: I'm really not interested in what the lecturer is saying! As soon as this thought flashes up, the attention is usually completely gone. So you have to try to find out why this topic is important to you. If you realize that the newly learned knowledge helps you with your hobby: Wonderful! If you think to yourself, "I just have to pass this damn exam if I want my degree," then at least that's a start.
Self-instuction based on learning and performance goals
The principle of this tip is actually the simplest of all. You want to be able to do what you have in front of you! Rocking the oral exam because you can just do it all is a super good feeling! The same goes for other things you want to do. Be honest with yourself when you wonder if you can do something already, because you probably have aspirations to do your thing well!
Environmental Control
Okay, this is pretty self-explanatory. If you want to quit smoking but still go on a smoke break with your buddies, the whole thing gets a lot harder. Control your environment so that there are as few temptations as possible to quit. Read through index cards in the pub...you notice yourself, don't you?
Set partial goals
Again, a suggestion that everyone has heard, but that doesn't make it any less effective. If you have a big pile of work in front of you, set yourself partial goals, because if you only see the big picture, you're much more likely to give up. It's best to combine these stages with the reward strategy, then very soon you can look at how much you've already accomplished instead of just seeing a big pile of work in front of you.
Use social sources
You don't have to go through this alone! Your fellow students need to do it too! Enlist the help of friends and family in your endeavors. Others can provide you with professional and emotional support when you've run out of steam or feel completely overwhelmed.