This is a tricky question because you have to answer a few things that you may not have the answer to yet. Your interests will develop over time and change as you get older. So, ask a lot of questions about different jobs and careers. Think hard about what it is you need to know to make the decision of whether that job is a 'dream job' or not. Build a list of the things you need to know. Maybe for you a dream job is traveling, being in charge of people, and putting teams of people together to create new technologies. Maybe your idea of a dream job is to work from home (remote) and spend all day working on a design in peace and quiet. Only you know what that vision is. Spend time on creating that vision as detailed as possible. Then start asking around in forums like this what jobs have all or most of your vision. You may not find an exact match, but you may be able to get close.
Once you think you have a job in mind, informational interviews worked for me in answering similar questions about what I wanted to work in. If I thought I had an interest in something I would search for people in that field or position and schedule some time to meet and talk. Meeting is better than talking on the phone or email. This also builds a great network for you. People like helping others. Simply ask for the help. I usually sent an email or made a direct phone call explaining that I was struggling to decide if their line of work was what I wanted to do. I asked for 30 minutes of their time to ask questions to help make that decision. I would offer to send them my questions before we met so they could have time to think about the answer (which keeps them from getting stuck in coming up with answers). Also, go big on this. Don't just try for a low-level person in the position. Find someone higher up to talk to additionally. You may find you end up with a mentor that can help you and they would then be in the field you both enjoy. Sure, it's a long shot, but you never get anything if you don't try.
An easy way to search for these contacts is a simple LinkedIn search for the skill or position. For example, "mechanical engineering" will give you a list of people with that title (sometimes previous jobs and not their current job) or "mechanical engineering, XYZ corp" will show people in a specific company with that position. You can use Glassdoor, Google (looking for news), and YouTube to research companies. Then it is simply a matter of connecting with them. You can always call the company and be honest with them on why you are trying to reach a certain person. You will usually end up with at least an email or a phone number.