How to improve singing?

It's not too late at all! The obvious answer to this question is to practice. A great way to practice singing is to sing along with songs that you love. During my initial foray into the wonderful world of singing, I used to extensively practice my singing while driving.

If you have access to an instrument this will greatly aid your vocal abilities since you will be able to accompany yourself, practice scales, and learn more about music simultaneously. I would suggest piano or guitar.

If you can find a good vocal teacher in your area, that may prove beneficial as well. You'll become a better singer if you develop good habits such as breathing, posture, enunciation etc. Not to say that these things are impossible to learn alone, but it does help if you can find a good teacher that adapts to your learning style. Youtube has many how to videos for all sorts of music lessons. It would be helpful to look around for some singing technique videos and see what you can learn from there.

In a nutshell, practice, practice, practice! Pick up a guitar or piano and start learning that as well. Practice singing scales and learn a little bit of music theory. Taking the foundations of music class in college is a great first step, but don't stop there. Take music theory, and look into possibly hiring a vocal coach for a short while. The most important things however are willpower and determination, with those 2 attributes it's never too late to begin! Good luck on your vocal journey!