Each and every time you post something, STOP before you submit, and take a moment to check, double-check, and triple check your spelling! Have someone else check your spelling if you need to. Use Dictionary.com if you have to. Just check it!
Nothing distracts from your message more than a misspelled word. You’re instead of your. Too instead of to. missing commas, or too many commas.
And nothing makes you less professional.
And just a note…if you don’t see a mistake until after you post, then delete it, chances are it was already viewed by dozens, or more, people. Social Media can be a cruel creature!