2 answers
Andy’s Answer
The main advice that I can offer is "practice." Definitely go to school and learn all that you can. Draw from life, don't just copy what other artists are doing. Understanding how things move in real life is the best foundation to making your animation look believable and compelling.
The Rhode Island School of Design (http://www.risd.edu/) is one of the top in the nation. But there are many other schools out there as well: Ringling College of Art (http://www.ringling.edu/), Art Center College of Design (http://www.artcenter.edu/), San Jose State University (http://www.sjsu.edu/), and the Academy of Art University (http://www.academyart.edu/).
They all have degree programs in animation but you can also get exposed to other forms of art as well.
Also, make use of online resources, YouTube tutorials are a great place to start but I don't think they can be as directed and tailored to your needs as a college curriculum. Once you're in school, they often have resources to get you internships at film and game companies which will help you to gain experience and understanding of the industries into which you are looking.
I hope that this has provided you with some good information and a starting point.
David’s Answer
Get to know as many animators as you can and try to work on various projects together. Animation is a team sport (in most cases) because most animation studios have multiple animators working on different projects (sometimes at the same time) and everyone is doing their part to bring a story to life.
To become an animator, it helps to find someone to teach you principles of animation and then challenge you with projects that require you to utilize those principles in small animated vignettes or animated shorts. Once you have a few projects completed then you can create a demo reel. With your demo reel (and resume) in hand then aggressively pursue an internship at an animation studio. Some of the best animators I know started out as interns and went on to work on Academy Award-winning films.