I got a job as a games tester and along with getting trained in testing games, I started to learn the terms and things involved in the Development process. I learned everything I could and got a job as a level designer mainly to do scripting. This was back in 2000 when Unreal had no documentation on how to make a level. Another designer showed me the basics of using Radiant, the Quake level Editor and Unreal to make levels. In 2005 I went to collage to get a game programming degree, that is where I learned the most at one time. I did internships at game companies as a programmer and have worked as a programmer since, sometimes at game companies, sometimes for other types of software like I am now.
If you really want to learn, go to school. Many community colleges have a 2 year program in game development and you could go from there to finish at a 4 year school with either an Art or CS degree depending on your interest and aptitude. I don’t recommend the private schools as they are too expensive. Still do tutorials, participate in game jams, do projects on your own as well. The school work alone is not enough but it gives you the foundation of knowledge.