Few decisions in life are more important than choosing a career. Since the big money usually comes only after one has worked their way up the ladder a bit, it is important to realize that changing ladders every few years can really hurt your chances. As a result, it is usually best to pick a career and stick with it, although not always.
Two closely related concepts govern the selection of a career; availability and opportunity. Availability means that you have chosen a job that will actually hire you. You have the right skills, training, personality, and other factors that get you in the door and on your way. Opportunity means that the job that is available to you will lead to something big down the road. Assuming that you have several available jobs to choose from, it makes sense to pick the one that has the largest possibilities for opportunity down the road.
Because opportunity is the key concept, give some thought as to what constitutes opportunity. A certain career may seem very desirable at the moment, but it could prove to be vulnerable to such factors as outsourcing or obsolescence. Some career choices are extremely portable, meaning that you can go live anywhere, and get a job if you are qualified. Others can be very geographically restricted. There are very few wheat farmers living in New York City or Boston, for example. Likewise, there is small demand for fashion designers on a Gulf oil rig.
Another important consideration is that there is greater competition for the most desirable career opportunities. This means that you must maximize your chances of getting in the door in every way possible. Be on time for your appointments, or at least call to let them know that you are on the way but slightly delayed. Make a point of being polite and courteous. Dress as if you are willing to go to work right now. Stay away from any suggestion that you are more interested in what they can do for you, than what you can do for them. Many interviewers get turned off by applicants who want to know about vacation time, how often raises are given out, and other considerations such as these.
When being interviewed, always remember that you are not the only nervous person in the room. Do everything in your power to make the interviewer comfortable being around you. Nobody is interested in hiring an individual that they are even slightly intimidated by. Pick your career with the future firmly in mind. Beat out the other applicants by being nicer, more efficient, and sincere in your desire to join the team as a team player. You are hopefully choosing a career, but they are the ones who ultimately choose you. Make it as easy on them as possible.