Making a reel is a must. There are a lot of guides on how to make a good demo reel. The biggest thing is to be good at what you're applying for. I've seen a lot of demo reels where the work is very sub-par. The second thing is, keep trying. I had to shop around to around 15 different companies before I even got a call back. It is hard, but it is possible!
Good luck!
Imagination is more important than knowledge.