Don’t learn at random, but approach vocabulary learning systematically.
Find a learning technique that helps you.
Create a pleasant learning atmosphere.
Try to integrate the foreign language into your everyday life, for example by reading texts in the language or watching films.
Don’t stress yourself, but don’t be too lenient either. Learning vocabulary is not always fun. But regular repetition is important to ensure that something sticks in your mind in the long run. In everyday school life, however, daily vocabulary learning is not always realistic. And having a bad day is absolutely fine.
Don’t lie to yourself just to get the learning over with as quickly as possible. It will come back to haunt you in the next exam at the latest.