Help with writing a good college essay?

Help with writing a good college essay?
I am working on writing my essay for college applications and I just need a little help with how to make it good. I know this essay is not suppose to be to flatter the school but to describe myself in a more personal way. Well, my grades have never been really good even though I try very hard to get good grades. Should I talk about some of my flaws as a student and how by going to college wish to fix those flaws? I really do want to make this essay as personally as possible without crossing any lines so that these colleges get to know more about me based on my essay and not judge me entirely on my terrible GPA and ACT scores although those are extremely important as well. Any suggests is welcomed. Thanks.

The admissions officers are actually just trying to find out what your writing skills are like. They certainly pay attention to what you have to say, but they are much more focused on a few other matters. They want to know whether you can take a really dull topic (like, “Why do you want to be admitted to our college?”) and turn it into something at least reasonably interesting to read. So act in your essay as if you were writing to a friend about your experiences. Focus on things you have been interested in and care about. That quality will show in your essay. Another thing they’re looking for is whether you know how to use language properly. Do you have spelling and punctuation mistakes? Do you write “your” when you mean “you’re”? Do you use the wrong words, for example “affect” when you mean “effect”? If you are not absolutely sure what you are doing, ask someone who has a good sense of grammar and mechanics to read your essay over for you.