Q: "I'm currently I'm trying to develop my own portfolio for the internship program, but I always come up new concepts in the middle of working on it. I keep thinking that the latest idea is better than the one that went before it and so I start all over again. How can I stop doing this!?"
A: This is a common problem of thinking the grass is always greener. The trouble is that if you continually keep switching, you lose the discipline to see something through. Being able to see a project through without distraction is a far more impressive skill to a potential employer than simply good work.
Improve your ability to focus and simply write the new ideas down in the back of a sketchbook. Keep adding to them and at the end of the project evaluate which ones are worth pursuing. Getting a project to 90%, signing it off and moving on to a new one is far better than striving for perfection and getting stuck on something for too long.