As a teenager, I spent 95% of my free time (as in, time outside of school) playing World of Warcraft.
First response, I'm sure, is that you're thinking, "Wow, so you wasted a lot of time."
Actually, no. Not at all.
I learned the most important lesson of my entire life.
Every single person I knew, parents, friends, siblings, teachers that found out (word got around school that among them was a pro gamer—at 17 I was one of the highest ranked WoW players in North America), insisted that I was wasting my life and that I would look back in regret.
They were all wrong. Every single one of them.
World of Warcraft taught me what it means to be disciplined.
For those that don't know the game, while I was competing (this was when 2v2/3v3/5v5 arenas had first been released), the system was based on a compounding algorithm. Meaning that each week, I needed to sustain my rating for at least 10 games, otherwise I would drop—significantly. The amount I would be able to earn in points (usable for new gear, which was ESSENTIAL) would plummet, and it would take me weeks to get back to where I was.
For players competing at an extremely high level, falling 2 weeks behind was not an option.
My parents, frustrated that their oldest child was spending too much time on the computer, enrolled me in a series of summer camps and music lessons to keep me busy. This tightened my schedule, forcing me to stay up some nights until 4 or 5 in the morning, get 3 hours of sleep, and then wake up at 7 for a summer camp.
While I was at camp, I would use my bathroom breaks and lunches to call up a friend, who was going to play my account for me while I was away—he was another top player, so I knew I was in good hands. He would ensure I hit the necessary amount of games for the week, at the very least.
I have example after example of stories like this. Stories that, on the surface, scream obsession, addiction, etc. But to me, they were the opposite. I was disciplined beyond common understanding. I possessed a quality that many my age had failed to demand of of themselves.
And it wasn't because I was extraordinary. I wasn't born some gaming genius. In fact, I'd never played an MMORPG before in my life, before World of Warcraft.
I simply loved the game.
I loved competition.
And I believed that if I worked harder than anyone else, I would become the best—doing what I loved.
By the time I graduated high school, I was being offered sponsorships, I had the most popular Mage blog on the Internet, I was offered a paid salary position on the blogging platform I was using, and I was a household name to any and every top World of Warcraft player in 2007-2008.
Why I quit is another story. Actually, it'll be a memoir. Confessions of a Teenage Gamer coming soon...
The point I'm trying to make here is that it doesn't matter what you DO. You could write code, you could take up meditation and yoga, you could buy a bunch of books and read them front to back and test yourself on the knowledge until you're blue in the face. At 17 years old, the most important thing you need to learn is DISCIPLINE.
Let me say that again.
AS A TEENAGER, THE MOST IMPORTANT THING YOU NEED TO LEARN IS DISCIPLINE.
Take a look around you. How many kids are ADD? How many kids set huge goals and then can't get themselves off the couch? How many kids say one thing and do another?
School doesn't teach you discipline. School teaches you how to bullshit your way through complacency.
If you want to be successful at anything, you need to learn discipline.
So how do you learn discipline?
Take what you love.
Do it relentlessly.
Push yourself to know more, learn more, create challenges, overcome those challenges—at the very least, set a time to work on your craft every day, and stick to that time NO MATTER WHAT. If you don't feel like doing it, good. Sit with that feeling. It'll come back again in the future about 10 billion times. Sit there for 2 hours with that feeling—however long your designated craft time is. Eventually you'll get so bored that your subconscious will say, "Eh, screw it," and it'll start working. And the next time you "don't feel like doing it," your subconscious will know it will be put in time-out and be bored to death if it doesn't, so it just dives in.
Discipline is a practice. It is an art. It is not a talent, it is not something you're born with. It is a piece of wood meant for you to whittle.
Get to whittling.