Most job advice revolves around activities leading to a job offer, such as building your résumé, preparing for an interview and networking efficiently.

However, once a jobseeker receives an offer, the strategizing isn't over. It's important to enter your new position with responsibility and tact, avoiding missteps that might put your job or professional relationships at risk.

“Starting a new job is counterintuitive,” says Marilyn Moats Kennedy, founder of Career Strategies, a management consulting firm in Wilmette, Ill. “People want to fit in and they want to be liked, but the first day they need to just get the lay of the land and figure out what's happening in the company.”

Kennedy says the first mistake a new hire often makes is to not make introductions to each person in the office. Rather than waiting for them to come to you, set a good foundation for future relations by being warm from the start.

As you get to know others in the office, make sure you act as sharp and professional as you did during your interview — and stay that way.

“A lot of people will stay dressed nicely for about a week and then slack off,” says Hallie Crawford, an Atlanta-based certified career coach. “It's fine to go along with the culture of the company, but you still don't want to become a slob at work. It really makes a difference in the message you send as a new employee.”

New hires also can make the mistake of starting with an unclear picture of what is expected from them. Don't be afraid to get clarification from your boss on your job description and the projects you should tackle first.

Kennedy also recommends taking the time to go through your predecessor's files to get an idea of the work he or she recently completed. “This seems elementary, but no one remembers to do it,” she says.

After your first week of work, it is helpful to schedule a brief meeting with your boss, says Kennedy. Explain what you have done and ask whether you are on the right track.

Offer your opinions thoughtfully. Crawford says many people enter a job with energy, enthusiasm and a genuine desire to make a good impression, but should approach situations with sensitivity.

“Sometimes people will barge in with all these changes, ready to reinvent the wheel,” she says. “But maybe the company has already tried some of the things you are suggesting and they didn't work, or maybe they have a tried-and-true way of doing things for a certain reason. Be tactful when you offer up your ideas.”

Finally, don't ever think you are too old, experienced or smart to make mistakes in your first weeks in a new job.

“After you work 20 years you figure you know it all,” Kennedy says, “but that's how you get trapped in some of these mistakes.”