You can improve your English and feel a little more confident with it by training yourself on different aspects. You can start right now by doing some online grammar exercises.
First, I encourage you to visit the following webpage
'GRAMMARBANK.COM' Then, choose whatever topic you may like to revise by double clicking the link below:
http://www.grammarbank.com/grammar-revision.html
You will find a wide variety of Multiple Choice Mixed Quizzes, Essay Writing Tips, Vocabulary Exercises, Short Dialogues, Spelling Exercises, Reading Tests, English Grammar Rules Explanations, Study Skills Tips and lots of Graded Exercises as well as ESL Grammar Tests to check your knowledge of English.
Finally, you will find out by yourself which aspects you should be reviewing to do your best and get the most of it. Help yourself and Enjoy the Ride!
ENJOY YOURSELF WITH ENGLISH!