Advertising is more like working in a restaurant then it is an office. You respect everyone's role and seniority, you work together to keep the place from burning down or going out of business, and you laugh at other people's expense.
So when it comes to emailing folks, imagine you're talking to a manager at a restaurant. Mr or Miss may not exactly be necessary, but always start off showing your respect for them and for their time. I always am a bit turned off when people refer to me by my last name... it makes me feel like they don't get what being a creative is.
If you're unsure, do start with Mr/Ms and see how they reply, if they sign off with their first name then you can call them that.
Don't ever write"To Whom It May Concern" or "Dear Sir/Madam". Ever. I will come through the Internet and smack you.
If emailing a Senator is a 10 and emailing your mom is a 1, think of emailing someone in the creative department as a 7. Show some personality but don't be too casual or familiar. (I am not and never will be "Neish" to you.)
Here are some other email tips
Dos & Donts
The Art of Emailing
Follow Up Email Template
