My mom has never been one to give me advice (she's big on me making my own mistakes), but she's always there to listen, which most of the time is all I need.
Seriously though, I think the best advice I can give is to not let people get to you. I'm the world's worst at taking to heart what people say and allowing it to ruin my day. Take yesterday for example--I found myself sitting at my desk crying because everything had gone wrong. I had to keep reminding myself that only I could control my mood. I could choose to sit and cry (which I did for a few minutes) or I could shake it off and move on.
So, to sum it all up...
Don't let people get to you; you control your own mood.
However, if you are unable to successfully lift your own spirits, make sure Mom is on speed dial.