How To Lose Credibility In .02 seconds
You might be surprised how people will judge you in a heartbeat. The moment you look like you don't know what you're talking about is the moment your reader/listener etc will raise their eyebrows and think you're a joke.
One thing worse than giving your audience the feeling that you don't know what you're talking about is poor grammar. When it's clear that you don't know the correct there/they're/their, you've lost me (in about .02 seconds)!
Here's a brief guide:
Your: Possessive | "Is this your book?"
You're: Short for 'you are'. | "You're a great person"
There: A location that isn't 'here'. | "You should stand there"
Their: Possessive | "That is their book"
They're: Short for 'they are'. | "They're over there"
Too: In addition, to the extreme | "I am coming too" or "I am too tired"
To: There are too many definitions | "I am not going to list all definitions"
That will do for now. If you're not confident which option to use, give it a Google... or I can take a look. Also, feel free to contact me with any freelance opportunities.