Never walk down the hall without a document in your hands. People with documents in their hands look like hardworking employees heading for important meetings. People with nothing in their hands look like they're heading for the cafeteria. People with the newspaper in their hands look like they're heading for the bathroom. Above all, make sure you carry loads of stuff home with you at night, thus generating the false impression that you work longer hours than you do.
Use computers to look busy. Any time you use a computer, it looks like work to the casual observer. You can send and receive personal e-mail, calculate your finances and generally have a blast without doing anything remotely related to work. These aren't exactly the societal benefits that everybody from the computer revolution expected but they're not bad either. When you get caught by your boss--and you will get caught-- your best defense is to claim you're teaching yourself to use the new software, thus saving valuable training dollars. You're not a loafer, you're a self-starter. Offer to show your boss what you learned. That will make your boss scurry away like a frightened salamander.
Messy desk. Top management can get away with a clean desk. For the rest of us, it looks like you're not working hard enough. Build huge piles of documents around your workspace. To the observer, last year's work looks the same as today's work; it's volume that counts. Pile them high and wide. If you know somebody is coming to your cubicle, bury the document you'll need halfway down in an existing stack and rummage for it when he/she arrives.
Voice mail. Never answer your phone if you have voice mail. People don't call you just because they want to give you something for nothing--they call because they want YOU to do work for THEM. That's the way to live. Screen all your calls through voice mail. If somebody leaves a voice mail message for you and it sounds like impending work, respond during lunch hour. That way, you're hardworking and conscientious even though you're being a devious weasel. If you diligently employ the method of screening incoming calls and then returning calls when nobody is there, this will greatly increase the odds that they will give up or look for a solution that doesn't involve you.
The sweetest voice mail message you can ever hear is "Ignore my last message. I took care of it." If your voice mailbox has a limit on the number of messages it can hold, make sure you reach that limit frequently. One way to do that is to never erase any incoming messages. If that takes too long, send yourself a few messages. Your callers will hear a recorded message that says, "Sorry, this mailbox is full"--a sure sign that you are a hardworking employee in high demand.