"What can I do to improve my vocabulary?"
Yes, reading is probably the best way to learn new words but there are many other, often overlooked, tools that can help ESL students increase their vocabulary. Word lists are compilations of the most frequently used words in English and are a great resource for students.
Here are some word lists that can help you in your studies:
The Oxford 3000 is a list of 3000 words that appear most frequently in English across a wide range of texts. The list also includes familiar words to most English speakers that are not used as frequently. These include parts of the body, words related to travel, and words used to describe what one means when they don't know the word for something.
The Oxford 3000 includes some useful features for studying. Words can be filtered according to CEFR level (A1- C1) meaning you can study only the relevant words for your level. You can also use the Oxford Learner's Dictionary Text Checker to check the difficulty of English texts and how many Oxford 3000 words they include.
Compiled by Dr. Charles Browne, Dr. Brent Culligan and Joseph Phillip, the New General Service List (NGSL) contains approximately words that represent 92% coverage for most general English texts. That means if you know all the words on the NGSL you should have no trouble at all in everyday conversation. The authors also compiled specialized lists including the New Academic Word List (NAWL), the TOEIC Service List (TSL), the Business Service List (BSL), Fitness English List (FEL)
The New General Service List (NGSL), the New Academic Word List (NAWL), the TOEIC Service List (TSL), the Business Service List (BSL), Fitness English List (FEL) by Browne, C., Culligan, B., and Phillips, J. are licensed by a Creative Commons Attribution-ShareAlike 4.0 International License.