Sounds too simple, right?
But for those of us with an eye for grammar and spelling, mixing up words like there, their, and they’re is more than annoying—it is an insult to the modern education system.
Another mistake that is all-too-common is the misuse of apostrophes, it’s versus its, and failing to make subjects and verbs agree in a sentence. It’s understandable if you feel like you can’t spell to save your life—get someone to spell check for you. Have another set of eyes (or two) look over your content and check for grammar mistakes. Invest in a copyeditor before you publish.
Because, really, there is nothing more unprofessional in online content than misspelled words or random apostrophes.