Clearly, it's in your best interests to take a hard look at your performance before your boss does. You also have to assess yourself from your boss's point of view. Maybe you'd understand someone who left 10 minutes early on a Friday -- but would your boss?

Robert Wilson is a partner in an employment consulting service called Job Bridge, as well as an author and a video producer of employment resources.

"At some point, you have to assess what you think is good and bad about your performance with what the supervisor thinks is good and bad, because he or she is the one that counts."

The following eight steps will help you help yourself:

Check Your Attitude

"Attitude is very important," says employment consultant Rick Waters. "I meet with a lot of employers, and they tell me the first thing they look for is a person with a good attitude. Doing the work properly is only part of the equation. The other part is your attitude.

"Do you come in late, leave early, spend time talking to friends instead of working, dress inappropriately, phone in sick when you want a day off, help yourself to company supplies for your personal use or are you rude to other people?

"Any of these things will earn you the reputation of someone with a bad attitude."

Be Reflective

"Every day on your way home from work, think about how the day went and what you accomplished. Ask yourself what went well, what didn't go well, and what you could have done better," advises Carol Coe.

She leads a group of teachers that help one another with self-assessment.

"Get in the habit of reflecting on your performance. Every week, set job-related goals for yourself. Do it in writing because that helps to clarify your thoughts. Then at the end of the week, view your goals to see how you did."

Kerry Mahoney, a university training and development coordinator, agrees whole-heartedly.

"If you are working on a project, ask yourself what went well, what didn't go well, and what happened. It's OK to make mistakes, but not the same mistake twice."

Assess Your Performance Against the Job Specifications

"There is no way you can assess yourself in a vacuum," says Robert Wilson. "At some point, you have to assess what you think is good and bad about your performance with what the supervisor thinks is good and bad."

1. If you have been given a job description, study it carefully and give yourself a thorough and honest appraisal. How are you doing compared to what your job description says you should be doing?

   If there is no job description available, then write out your own specifications for the minimum standards for performing your job. Then, rate yourself on how well you have met those standards.

   "It's very important to be both honest and thorough," says Wilson. "This is for your eyes only, so be brutally honest."

2. If there are different aspects to the job, break those tasks down into a list and write down what you have done to complete each task. Once again, this is for you alone, so there's "no need to sugar-coat the deficiencies," reminds Wilson.

   "Write down the good things you have done, and also the things that you have been able to cover up. Then write the things you haven't done at all and where your below-average performance is sticking out there for all to see."

3. Compare your self-assessment with any physical documents that confirm your self-assessment.

Keep a File

It's important to keep copies of any documents that directly or indirectly give some indication of your performance level.

This could be letters, memos, reports, proposals or e-mail printouts that give some clue as to your participation in departmental activity. Be sure to keep records of any occasions when you may have exceeded expectations or gone beyond the call of duty.

"Maybe you managed to help out when there was a crunch," says Wilson. "Keep records of it, because you may forget later on when it's time for your performance evaluation."

The record will be useful if you need to defend yourself against a negative review from the boss, or for documentation when asking for promotions or raises. It is also useful for updating your resume or for collaborating accomplishments for your next job.

"You should keep this file at home," adds Wilson. "That way, it won't be found on your day off and misinterpreted by people at work."

Find out the Supervisor's Expectations

1. "Make every effort to find out what the job involves from the boss's point of view," says Sylvia Ho, a lawyer specializing in employee relations. Ho is the workplace coach for iVillage and the employee advisor for the Monster.com job board.

   "Often on the first day, the boss shows you the ropes and invites you to ask for a meeting if you have any questions later on. Take him or her up on that offer."

   "Establish communication with the supervisor right from the beginning," agrees Mahoney. "Ask if he or she is satisfied with your work and if there are suggestions as to how you can improve."

2. Try to discover any additional expectations that the supervisor may have, then meet or exceed those expectations. Look around you, talk and gather information.

   For instance, if you are a cashier, there are some expectations that go along with the job, such as showing up on time and being accurate.

There may be other specifics that the supervisor appreciates. Try to find out what they are. For instance, "If you are a cashier, there may be someone to bag the groceries. You might help with the bagging. This would be exceeding expectations," adds Ho.

Get Feedback From Others

The experts agree that getting feedback from other sources is very important to your self-evaluation.

1. "Ask some friends you trust if they agree with your evaluation. Or approach someone in your organization that is obviously doing a good job and is well respected -- perhaps someone from a different department.

   "Tell them you are not fishing for compliments, but you are looking for an honest appraisal," says Wilson.

   "It's important not to depend on just one opinion, though. You need at least two, and if they are very different, you will need three."

2. When you identify deficiencies, develop a strategy for eliminating the weakness. "If you have already done this, you will be way ahead of the game," adds Wilson.

   In your records, write down what you have done to improve these areas and what the results of your efforts have been. During your formal performance evaluation, you will be able to show the supervisor what you have done.

   "Your supervisor will be very pleased that you have gone this far on your own. He or she will be trained to help you work out a way to improve still further," says Wilson.

3. "Find a mentor," suggests Mahoney. Mentors are supervisors or colleagues, usually in a senior position to you, who offer guidance, feedback and advice from time to time. Look around your organization and find people you admire. Talk to them and see if they are willing to give you some guidance.

Be a Team Player

"Be a team player and not an independent merchant," says Ho. "You need to understand the dynamics of the group. If you are not a team player, you will get thrown out of the loop."

Newcomers to a workplace are not automatically accepted into the group. "The group has to rediscover how to work together," says Wilson. Every workplace has "unwritten rules" -- the expectations that don't appear anywhere in writing, but which people must abide by in order to be accepted as one of the team.

"Joining the team depends on fragile interplay, communication, ability, the hierarchy of who reports to whom and the egos of the people involved at every level.

"In some groups, you will find measures of fear, envy, jealousy, disrespect, and you will have to deal with those things as well," says Wilson.

"Really watch and observe how things are done," says Mahoney. Network, research, and talk to people. "And in the first few weeks on the job, it is a good idea to do more observing than talking."

"And be really careful about dating someone from work," offers Waters. "It is especially unwise to date someone that you supervise or who supervises you. A lot of people don't understand this and they get into serious difficulties."

Plan Ahead

Think ahead to where you want to go in the organization or in your career. Look for ways to increase your responsibilities. "If you are not busy, take the initiative and figure out how to get some new skills. Look for people who are busy and ask if you can help on their project," advises Mahoney.

Have a development plan for yourself and let your supervisor know your interests.

For example, if you are doing well in your present job but you are interested in learning public speaking, you might ask your supervisor if they would give you some added responsibilities where you will have an opportunity to practice speaking in public.