A philosopher is anyone who not only looks at the world around them, but also asks 'why?' at every conceivable opportunity, and strives to understand the answers to those questions. You must see, for example, yourself not just as part of a species roaming and conquering our planet, but ask why we feel the need to be here, hold that, be called this, understand how those things over there work and how we can make them work better for us.
Becoming a philosopher.
Here are my tips on how to become a philosopher. They might have been aforementioned in the previous answers but I'll put them down for the sake of entirety.
1. College
2. Yourself
3. Teach
4. Religion
I will go into detail about all of the different ways to become philosopher.
1. College
To become a philosopher here is like in any other course you might do over the course of time. You pick philosophy as one of the things you want to do and then you take the course. Simple as that. This won't make you the best philosopher or the worst but it will help you greatly on your way for further enlightenment.
2. Yourself
This is one of the options that cannot be absent from the others but the others can be absent from this. This option is like teaching yourself the piano or snow-boarding or anything else. It's not hard to do but it's easier if you have other ways of pushing yourself along. As in, if you "learn" the piano and then go for lessons then continue with teaching yourself. Now if you want to teach yourself, you have to want it badly enough to do things you probably aren't prepared to do right now. You have to know where your morals lie before you start teaching yourself because, one little slip in your judgment and you don't have morals to lean on, you might be the next contract killer, suicide bomber or something else like that.
Ex: You have a revelation that goes like this. Life doesn't matter, we're all so small anyways so why would killing be such a big problem. God doesn't exist and neither do his laws so why would it matter if I just kill someone. It's mot a big deal. His life is worth as much as mine so I can do whatever I want to him.
Without morals such as the 10 commandments, or other laws like that one we would be in a free for all world without any love because it makes no sense. Why would you love someone else when nothing is stopping you from only loving yourself.
So self-teaching is great but you need to have morals and you need to want to truth enough to pick out false judgment. This is essential for philosophy since it's a game of thinking but you need to have a good foundation.
3. Teaching
You learn so much more quickly when you teach others. It's proven and I've seen it on posters and such. I forget exactly what the order is for learning percentages but teaching was on the top of that list. Philosophers seek enlightenment which is a fancy word for knowing. Since you learn the best when you're teaching why not teach philosophy. You will have an experience unlike any other. You will learn quickly if you give seminars about your ideas because you won't just be thinking about them in your head but saying them out loud and helping yourself think through your idea more completely.
4. Religion
Now theist philosophy is much harder than atheist philosophy because atheist philosophy is throwing darts at religion when the average Christian, Buddhist or Jew is throwing them at his own faith inside. I know that there is doubt and it's not unlikely to find someone struggling with there own religion. The human mind is seeking learning always so they ask themselves "How did god...." a lot. They don't want to be wrong in something that shapes your life so much as a religion should. Now this is one of the hardest things if you start it now, when you're older. Your friends are probably so full of things that aren't good for your religion and it's fairly hard to find good people who are like you. This is a fairly hard way to become a "philosopher per say but it's a very rewarding one that will give you faith and bring more meaning into your life.