It's important to look serious if you want to be taken seriously. Which means no smiling. The giggly, happy ones are often deemed shallow. A perennial frown and a supercilious expression help. You could master this look by drinking a bottle of bitter gourd juice every hour.
Don't make conversation with people unless they are the hoity-toity type. As for the others that don't fit this bracket, give them a once over and disregard them as lesser mortals. I mean, who else can be more important than you? Stay aloof. And no, the social networking sites don't have the pleasure of having you as their member.
Always walk up and down while talking on the phone. Pretend as if you're striking a business deal. Even better if you have an accent. You can choose your accent based on which country leads the currency chart. Also when you speak ensure you have an audience. Drop big names and bigger words.
Look busy all the time. Carry around a big book, preferably one that no one's ever read. That way you can evade conversations based on the book. Never volunteer to do anything minor. For example, if your colleague's computer isn't working and he / she needs your help or if someone just needs a cup of coffee, don't be the one jumping up to be the helping hand. Tell them you have other things to do — such as writing the Governor's speech for him, even though all you're doing is playing Solitaire.
Finally, get the look right. Avoid pink and other bright colours. Those are for the frivolous. Black, brown, white or anything boring and staid works.