The cover letter is extremely important when searching for a job these days, and in order to really achieve maximum effectiveness it has to be nearly flawless. This sounds a little intimidating, I know, but I figured that for this article I'd help you out by listing a few of the things that are commonly done incorrectly on a cover letter, so that you can make sure to avoid doing them yourself.

1) Not writing a cover letter! The biggest mistake anyone can POSSIBLY make is to NOT write a cover letter. It's practically essential to make positively sure that you have a cover letter! Not having a cover letter not only makes you look unprofessional or lazy, it also makes you lose out on an incredibly valuable edge you can have over the massive competition!

2) Writing in informal style, with spelling or grammar errors. Come on people, this is business stuff here! Treat it like it! Language should be completely formal, business-appropriate. Address the person you're writing by the appropriate title, be it "Mr.," "Mrs.," or "Doctor." Whatever's appropriate. And PLEASE ditch the spelling and grammar errors. Check your work thoroughly, because even a single error can stare out from the paper as a glaring neon sign of unprofessionalism. It will turn off any potential employer reading it, and you'll be on your hunt for a job for a lot longer.

3) Not being proactive! This is less about the cover letter itself, and more about the follow up or distribution process. A cover letter is potentially your most powerful tool towards getting that job, so why squander such a valuable resource? Always make sure that your cover letter is pointing towards getting an interview, and follow up! Take initiative and get the things you want. Don't sit around waiting for a call from the the employer, pick up the phone and make that call. Things won't be handed to you on a silver platter, you have to get them for yourself!

And always remember that a single excellent cover letter that's well-researched and highly-targeted at one particular business will do way better than a hundred "assembly-line" generic cover letters sent out to various random businesses. Employers want you to know something about their company, and why you'd be the best fit for it. Be proactive...do your research, and make it clear that you personally chose their company.