Words are the bricks which we use to build relationships with other people to:
Step #1 Absorb
Dive into the sea of available information to find out more and more words. Even if you do not understand them all, soon enough you will discover that through exposure to the information, you will have gained enormous amounts of building material. When you study a new language, the trick is to be surrounded by it each day, to get into a bubble that consists of music, literature, television, conversations with natives and even your own thought processes subordinated to that language, trying to absorb as much as you can regarding all aspects of life. The same applies to deepening the vocabulary in your language. The only difference lies in choosing the information that really applies to you. Language is a giant web that covers all aspects of life, so if you want to build an academic vocabulary, read academic works, and absorb all the words that you find interesting or educational. You will soon find out that they have stayed with you on a subconscious level.
Step #2 Revise
In order to turn the subconscious material, you have gained during step one, into usable bricks you need to revise. The process of revising consists in fully understanding the deep meaning of the words, while getting them out from your subconscious into your passive reservoir of words. These are the words that you fully understand and will be able to recognize in spoken and written speech, but still cannot use by yourself in your active vocabulary. You will soon realize that some words make you stumble on your way more often than others. These are the words you will need to pay special attention to, as they are key words in the academic world. Check dictionaries, compose word lists, underline them in academic texts. It will be a useful exercise to memorize them and bring them to the third stage.
Step #3 Recreate
The third and final step of your vocabulary-building program is to apply those words in practice. In other words, it is a high time to take those bricks from your passive reservoir and bring them to the construction site, turning them into your active reservoir. Apply those words in your oral presentation, speeches, while discussing controversial issues with your groupmates and colleagues. Do not be afraid to use them in written compositions too: anywhere you can apply them without losing the integrity and style of the work. It will be a great exercise to figure out which words can apply to which situations, and soon you will be confident enough to use them without too much stress and overthinking. Remember, that only after you can successfully use your vocabulary in practice, you will have truly achieved the next level of linguistic proficiency.