How to Improve SQL structure query language

How can i improve my structure query language SQL. Suggest me your answer i am from India want suggestion from you all people.

Try this http://www.w3schools.com/sql/default.asp

There's a book of 12th class sumita arora it has a brief of sql to start and if you know everything then nothing is better than creating tables and trying different option on it in xampp or ant mysql software
you can only learn by practicing and using it more frequent