I have put together some helpful advice on starting a new job, and thought I would share them with the community. This advice stems from my own personal experience over the years. Any comments/additions are appreciated. Thanks to everyone in the CB for their suggestions.

Exude self-confidence and intelligence.
Don't be afraid to ask questions. But don't bog down your trainer with dozens of questions. No one will enjoy holding your hand, especially if they are busy with more than just "showing the new guy around". Some companies excel at training new hires, but it has been my experience that few places give training much thought. Live with it.

Also everyone will be watching you closely in the beginning, so it's best not to make too many mistakes or look like an airhead. Try to be sharp and don't show fear. Be confident in your ability to perform your job tasks, even if they haven't come into focus yet. Let your behavior reflect that the company's decision to hire you was the right decision.

Try to fit in
Be yourself, but try to belong. For example, if you notice everyone wearing nice clothes, consider wearing similar attire. For some companies, image is important, and if you do not fit into the company's "image", then you might find that you stick out like a sore thumb. I knew one recent college graduate who consistently dressed below the standards of her coworkers. By the time she realized her mistake, she already had been transfered to the worst office in the company.

Don't be late to work
This one is a no brainer. I always make it a habit to arrive early for the first few weeks. No doubt, someone will be watching you when you first start. So don't be late, as tardiness always leaves a bad impression.

Don't step on any toes
Be respectful and watch out for those toes! Be careful about your comments concerning other coworkers, as comments can often be misconstrued, especially when others are just getting to know you. What you say in jest, may be seen as an insult to someone unfamiliar with your sense of humor. Be careful with any changes you make. For example, changing the .login file which will affect anyone else who uses your account.

Be paranoid
Many employers spy on their employees at work. When you have dead time, try spending it on something work related, like how something works, instead of building your fantasy team or composing long personal emails. Don't hunt for other jobs. Don't instant message! When you are on the clock, you are there to do work. Sportscenter will be there when you get home. Just do your job and let them watch.

Cast a critical eye on your new job
While you know others will be judging you, so should you be judging your new job. Did you make the right decision to work here? It is better to leave early, then to prolong your stay in hell. Ask yourself some questions:

Your answers to these questions will change over time, but if you already can answer 'no' to any of them, then you should consider bailing out. The sooner you leave, the better. Be careful about advice from family and other concerned voices. Only you really know if this new job is the right choice for you. Listen to yourself.