This is hard, because freshman year, you have nothing. Probably no internships, no skills, no nothing. So what do you do? Well if you are reading this early enough, and you care enough about getting a job, then you can try to get something in before you go to college. But most likely it's already too late anyway. So what do employers even care about? In high school I came from the competition math crowd. And it was already evident in high school that companies wanted to hire people who were good at math. So something like having good USACO/USAMO scores was already a way to get your foot into the door for a first round interview. I am not familiar with what the qualifications are for other fields, but it should be similar. Again, the reason you are being rejected as a freshman is not because they don't see your potential. You are a blank slate and your future is completely unknown. So it makes no sense to take on the risk of someone with no track record, they would rather take someone who is older and has some experience.
Some people mistake this for a chicken and egg problem. If you can't get an internship without prior internship experience, how can you get an internship? Well there are usually levels of internship desirabilities, and the ones at the bottom are easier to get. So you just have to figure out where you can get in.
With that said, if there is one thing that you can use to raise your stock at a job conference, is to show enthusiasm. Research some companies you care about. It's sort of like college, are you really going to attend Bob Smith School of Engineering and bring the next generation of astronauts to Mars? No, but if you can show that you are passionate about some problems, and they relate to the company. And you sound motivated and someone who wants to work there, they might give you a chance. Most people are wage slaves anyway, seeing someone who is excited at least brings some fresh blood to their company.
Go to the career fairs early. If you are an ECE or CS major, Let's Talk is one of those major-specific career fairs that you must go to. Finding a job is similar to dating. If you don't bring anything to the table, your employer is not going to be interested in you. So, it's not about just playing numbers game. It's about having the qualifications, and also playing the numbers game.
I would read the Academic Coaching guide in the Resources section about how to set up interview schedules and journals. In general, what you want to make sure is that after each interview, you reflect and become a stronger candidate.
- A guide I originally wrote for Academic Coaching
- Quant Trading Interview Guide: while this is more applicable to people applying to technical jobs, this gives an example of how to systematically prepare for a type of job position. From fundamentals (math, theory) to more applicable parts, and behavioral aspects that are tested on the job.