Changing careers is stressful. But you can cope with -- and overcome -- the challenges.

First, you need to understand the most common obstacles that career changers face. Then you can begin planning how you'll combat them and persevere.

In the second part of our series on changing careers, Richard Bolles, the author of "What Color Is Your Parachute? 2003: A Practical Manual for Job-Hunters and Career-Changers," offers advice that will help you throughout your career change. His tips can help you stay your course and not get discouraged.

Friend or Foe?

People whom you don't know well are the most helpful during a career change, Stanford professor Mark Granovetter's groundbreaking study found. The study showed that people with weak ties to you (those you know casually and see infrequently) are more useful than people close to you.

Granovetter also found that jobs identified through casual contacts were generally better paying and more satisfying than those found through close contacts.

Close friends and family members may have trouble envisioning you in a different career. People closest to you "have a huge investment in keeping you as the kind of person they've always known," said Bolles.

To expand your network, make an effort to contact acquaintances and meet new people. You can also attend professionals events, join an industry association and meet other job seekers online.

Visit one of Yahoo! HotJobs' career communities here: http://www.hotjobs.com/htdocs/client/splash/communities

The Money Issue

If you want to change careers, your salary expectations need to be realistic.

Many people stop their job searches because they are disappointed with prospective salaries.

"[Others] settle for something that's half of what they want" said Bolles.

Career-changers shouldn't necessarily expect to take a pay cut, especially if they have transferable skills. But, if they do accept a lower salary, many find it a fair exchange for a more rewarding career, said Bolles.

Yahoo! HotJobs' salary calculator can help you determine what you could earn in a new career: http://hotjobs.salary.com

It Doesn't Happen Overnight

On average, it takes four years to change careers, according to Herminia Ibarra, the author of "Working Identity: Unconventional Strategies for Reinventing Your Career."

The process of changing careers is one of trial and error. You'll likely even face a few disappointments and failures.

The key to persevering is having realistic expectations of the time and effort required.

"One of the reasons my book has been so popular over the years is that I tell people what they'll normally run into, so that they're not surprised. Then they don't take it personally when they run into obstacles," said Bolles.

Focus on small victories to keep your momentum and stay motivated during your career transition.

Enthusiasm

"Enthusiasm is the key to making a career change," said Bolles.

"One-third of all job hunters and career changers gets so discouraged within one month that they quit," said Bolles.

As you go through a career transition, enthusiasm can help you meet the challenges and overcome the obstacles.