In response to a query by nativewriter here are two great links to solve your problems with Commas. When I was young I was taught that the rule with commas was “If in doubt, leave it out.” I have many students who do just the opposite and throw commas all over the place. But these pages will teach you when a comma is essential:
The following site has really detailed information and exercises:
Work through these and I am sure you will finally sort the issue!