First of all: check your spelling. The easiest way is to write the text in a software which will underline the misspelled word whenever it appears.
Do not babble. In other words be short and right on point. The average Internet user will hit the back-brows button instantly unless the text gives him (or her) a satisfaction in reading it or some valid information in return.
Write with passion; don't try to show off. It shows.
Don't use hard words just to "brag". It shows too.
Give us your own thoughts. Be personal. We love it!
Don't be too formal, it will only sound boastful and pretentious. The web has too much of that already.
Read some of our articles/interviews. If you think that your submission fits and you have read and followed the above directions, don't wait a second longer... submit!