While I don’t think that these mistakes make people look stupid, as ZDNet says in their article entitled “10 flagrant grammar mistakes that make you look stupid”, but I do agree that they can stick out like a sore thumb to certain people, making your writing look less inteligent. I know that I have made many of these mistakes myself having failed an English grammar class when I was in high school.
Here are the top three listed:
#1: Loose for lose
#2: It’s for its (or god forbid, its’)
#3: They’re for their for there
I struggled for a long time with the third one, the difference between their and there always bugged me. The list is a great refresher, and might remind you to be a little more vigalent in the words you use so that you always come across as professional and easy to understand as possible.