English Vocabulary

Read.

Really. Read everything you can that is likely to have good grammar, be well written.

You will learn sentence structure without realising it. You will pick up word meanings from context and your vocabulary will expand every day.

Improving vocabulary usage is a never ending process. One book that I found to be very helpful is "Tooth and Nail: A Novel Approach to the New SAT." I contains approximately 1300 challenging words and you basically learn words in context.

Use a book like that, and read, read, read.

Also increase your Lexile level as your vocabulary improves, so try to read literature at your level.

If you don't know what Lexile level is, Google it.