Yes - writing a cover letter will definitely help you land a job! I know some people stick to a template that works for them, and that's great, but it is also very important to do some research on the company and the role you are applying for.

I have found success with my cover letters when I write a sentence or two about the company's most recent success or highlights in the news. Then I go into why I am a good fit for this specific role and give impressive but brief examples. My best cover letters are only a page!

Best of luck and don't give up! You never know what is in your near future :)