Professional conduct starts before you enter the employer's door. It starts before you begin to look for a job. It starts with you AND your attitude.
How you interact with other people can make the difference between enjoying your work or hating it. There are some basic tenets of conduct on the job that will provide you with a basis for behavior. Here are three for your perusal.
First, remain calm in all circumstances. No one likes a hot-head and people who lose their tempers show a distinct lack of self-control. Respecting the needs of others and allowing for discussions of all kinds, even when it isn't the best situation in your eyes, shows true character and a willingness to work with others. Employers are always looking for people who can mediate and work their way through difficult situations.
Second, keep your personal life at home and your professional life at work. We all go through struggles. No one is immune to pain, anger or sorrow. It makes life more bearable for everyone if separating the personal from the professional can be accomplished, though. If you need to work through something that is going on at home, then take some time off from work. Otherwise, your productivity decreases and your ability to maintain positive relationships on the job suffers.
Last, give your job 100% of your attention. Very few people actually do this, but it can make a tremendous difference in your advancement potential. If you gave just 10% more than anyone else in your department on a consistent basis, your productivity would be evident in a very short period of time and you would rise above your peers. Get rid of anything that wastes your time, such as the internet, cell phones or checking email 15 times per day if it isn't essential to your job responsibilities.
Professional conduct on the job means many things, but it all boils down to treating others the way you would like to be treated and doing the very best job you are capable of doing.
It can make the difference between getting hired or not getting hired (in a job-search setting). It can make the difference between getting promoted or not getting promoted within an employment setting.
Make the most of your employment opportunities. Excel at everything you do by devoting yourself fully to the tasks and responsibilities that present themselves to you. That not only includes work-related duties, but also getting along well with the people you interact with each day.
Your co-workers will notice and your boss will too.