Nobody learns a new language by "cramming" words into their brain. It just doesn't work that way. Learning a language takes time. There's no way around it. And so, one of the most important things you can do is to be consistent in practicing a little bit every day.
I know, you've heard advertisements about "new" methods that make learning really, really fast. Sorry. There is no magic bullet. If you are going to develop any degree of fluency, it's going to take some time, and that's why it's so important that you pace yourself.
For example, if you just learn three new words every day, in a year you will have learned more than a thousand words.
A thousand words!
So try not to miss your daily practice session. If you don't feel like studying, pick some activity that is easy and doesn't require much effort. Practice the vowel sounds. Count to twenty. Recite some easy dialog. Even if you only do a little bit, that is so much better than doing nothing at all!