Theodore Said:

How do I improve m grammar, language, etc. ?

We Answered:

Graff, Gerald and Cathy Birkenstein. They Say I Say. Norton, 2006.
Hacker, Diane. A Writer’s Reference, latest edition, Bedford/St. Martin’s: Boston, 2003.
Norton Reader, latest edition.
Literature - compact edition - An introduction to reading and writing by Edgar V. Roberts and Henry E. Jacobs.
You can get all those books used.
They are all invaluable.