Obviously you are looking for a job you will enjoy doing and you have spent a lot of time training for. As an example, if you study as a chemist then you will expect to be doing chemistry in your job. But I used to train lab technicians and it was common would find my students had degrees in subjects such as English, political science, and history. They never thought they would end up in a chemistry lab but they apparently found it tolerable as many had been employed as such for more than 10 years.
But ultimately I must tell you this is a much bigger question than you might think. Indeed in any one situation whether the job is really "for you" may be simple, the reasons it may or may not be can be of all and many kinds. You might not like the commute, you may find your lab/office may be in a dark basement. You might find your work space is extremely limited. You might find the corporate culture is not to your liking. Worse yet, you may find a fantastic personality clash with your immediate supervisor... honestly these things can happen with no rational explanation! There is so much more! I can say I have found myself in situations where my place of employment was blatantly doing things that were unethical and even illegal. I did not stay with them very long!
But you must also remember often these things are only temporary. Every company I have worked with had morale ups and downs. If you come in during a downswing it may not be pleasant but that does not mean it will last very long. Ultimately it comes to chance and, perhaps, the industry you choose. If your industry is in under financial stress or if it is subject to changes in government etc. it may never get better. As on toxicologist I used work with said "Life is a dice game!"
If you can scope out a potential employer very well before you even go for the interview, you may be able to tell if it is the place for you. Social media may help you with that. Certainly Google or some other web browser will work for you as well. Never apply for a job for which you know nothing about the job or the company ahead of time.
There is likely much more I could say here... lots of personal bumps in the road! I hope you will go into all this with eyes wide open. May you find a wonderful job that suits you perfectly even on your first time!
Dr. R. Detra