There are vocabulary lists out there you can google.
As part of your study, you should make it a goal to learn 10-20 new words per day. This will increase your vocabulary rapidly.
Remember that it is not always necessary to know the dictionary definition of a word, but you must always be familiar with its usage.
A lot of students find it easier to learn new words when they are used in a sentence. This is a good way to learn new words.