Whether an employer has a formal probationary period or not, new hires are given only so much time either to prove themselves or walk the plank. New employees should therefore have an agenda for their first three months on the job to demonstrate they can fit in and perform – in that order.

Most people make the mistake of keeping their nose to the grindstone because they think that’s what the boss expects. While a strong work ethic and suitable technical or trade skills are essential, “It’s the other stuff, the soft skills, that separates the keepers from the losers,” said Ford R. Myers, president of the executive consulting firm Career Potential, LLC.

Initially, employers aren’t scrutinizing a new worker’s competencies, which they presume are givens. “They’re looking to see if the person aligns with the company’s values and culture. In other words, does the person fit in,” Myers said.

Therefore, the corporate culture should shape the newbie’s agenda. “Someone who is a quick study can pick up cues about the organizational culture and assimilate accordingly,” said Violet Ho, an associate business professor at the University of Richmond in Virginia.

However, new workers ought not to rely entirely on observation. Get involved. Schedule lunches with colleagues. Join the company’s softball team. “Integrating into the organization’s informal networks can often yield information that may otherwise not be freely shared with outsiders,” Ho said.

A new employee’s first order of business, then, is to start building an interoffice network, learning names and cultivating connections with employees of all ranks.

At the same time, the newbie must establish a reputation for honoring commitments and producing tangible results. Myers recommends keeping a “success file” to track contributions, accomplishments and kudos received from others. At the end of each month, the employee should provide the boss with a bulleted list of successes.

New employees should sit down with the boss on day one, and on a regular basis afterward, to stay clear on what’s expected of them and whether those expectations are being met.

Young or entry-level employees in particular should not set out to be supernovas right from the start. This alienates colleagues whose help they’ll need to learn the ropes.

“I tell students to start their careers learning how to be a good follower. It’s not what they want to hear, but you have to know how to be part of a team before you can learn to lead one,” said Emily Bennington, author of “Effective Immediately: How to Fit In, Stand Out, and Move Up at Your First Real Job” (Random House, 2010).

Nevertheless, confidently voicing your opinions in a respectful way is important from the start, said Kurt Weyerhauser, managing partner of the executive search firm Kensington Stone. “What most people don’t realize is that the patterns they set within the first three months of starting a new job often become entrenched for good. While wanting to watch and listen may seem like a good idea, it can result in marginalization.”

A note of caution, though: “Don’t spend time talking about ‘how we did things at my old workplace’ since that gets annoying very quickly,” said career coach Terri A. Deems of WorkLife Design. “But if something you did do before is really relevant to this new place, bring it up in terms of a question: ‘Has xyz been tried with this?’”

New employees often are afraid to seek help for fear of seeming incapable, but it’s generally better to do so than to perform beneath expectations.

Finally, new employees mustn’t forget to thank or report to network contacts and update their professional profiles online. “In your first few weeks, if anybody wants to learn more about you, they will likely do a Google search on your name,” said Stefanie Smith of the consulting firm Stratex. “Do you really want them to see an outdated title from a prior company?”