When companies want to expand their reach, they often turn to strategic alliances, teaming up with other firms so both can do more.

In today’s more entrepreneurial workplace, ambitious professionals need to start thinking along the same lines, looking for situations to work with colleagues toward mutually beneficial goals.

The days when employees could count on their supervisors to look out for their career interests have passed. Most bosses are too busy and overworked to really help their employees advance, despite their good intentions.

From talking with hundreds of very successful professionals and entrepreneurs every year, I know there are plenty of opportunities for most to work with supportive colleagues and contacts behind the scenes to help each other advance.  If people in your professional network can see that when you get a new job, you are likely to help them, why wouldn’t they want to assist you—and vice versa?

By posting a great LinkedIn review for you or putting in a good word with a hiring manager they happen to know at your target company, they will be helping themselves, too.

So how do you build these types of relationships? It usually starts long before you’re interviewing for a job.

How to Build Strategic Relationships

Be generous to their colleagues—without seeking payback.

The folks who always end up with supporters in their corner are the ones who have made it a practice to actively help current colleagues, clients or suppliers. Seemingly small favors, like passing along a sales lead to a supplier or pinch hitting for a colleague who is sick, will stick in their minds for a long time afterwards. Of course, these gestures need to be genuine. No one wants to feel like you’re looking for a quid pro quo trade if you help them out.

Seek advice—not favors—from influential colleagues.

Instead of asking supporters to put in a good word for them at a company where they want to get hired or with a potential client, these savvy professionals seek tips on how to navigate the interview or sales process at a particular company.

This low-pressure approach keeps these informal advisors from feeling burdened by yet another “to do.” And often, they’ll appreciate being asked for advice so much that they will put in a good word for the asker anyway.

Travel in a pack.

You’ve probably seen a particular group of like-minded colleagues move together from one company to another in your industry.  This doesn’t happen by accident.

When interviewing for a big job, the highest ranking person will typically sell a future employer on the fact that he can put a strong team together quickly—all the while making sure that his or her key supporters are game for making a move. Star executives know that companies value the fact that they can bring together a high-performing team quickly and hit the ground running, so they play up this strength in the interview process.

Whether you’re an executive type or someone who likes to support an influential colleague by executing on his or her vision, these types of alliances can be invaluable in opening professional opportunities.

When you find you are working with an amazing group of colleagues, make an active effort to strengthen those bonds even more. That way, if you’re not happy where you are, you can look for ways to make a move together, with the idea of getting you all on board over a period of several months to a year.

It’s not easy to pull off, but it’s worth trying.

What could be better than getting a great new job—with a terrific team you already know?