What do you do when a lot of words pile up ? How will you remember all of them ? How will you use them ? What if you use them in a wrong place and wrong time ? I think there is no easy way out. The more you take a risk of using them, whether right or wrong, the better your chance of use it correctly.
There are some tips which may help you.
1. Make your own vocabulary list.
2. Classify your words into three groups:
High -frequency words
Mid- frequency words
Group them. Then study them. This will be less overwhelming for you.
3. Learn a word in a context. Write the sentence where you got it. Make elaborate note. Connect it with other words, and compare it to the similar words you may know in that language or another language.
4. Make flashcard with the word and use in a sentence.
5. If you hear the word spoken by a native speaker, make a mental note of the situation that person used that word. That word may demand a certain register.
6. Use the new word whenever you can.
7. Allow yourself to make mistakes.
8. Combine all skills related to a particular word. Learn how to pronounce it correctly, learn how to spell it right.