Work at your craft, write daily, and follow your dreams because dreams do come true.
I write because I love to. I'm very, very fortunate to have found something that I love doing that also earns my living. But to be honest, I'd write even if I weren't being paid to.
Write for the love of writing and you can't go wrong.
Writing has always been a sanctuary or a refuge for me, any time I'm stressed or anxious or worried I find that a couple of hours expressing myself by writing always seems to have a calming effect on me.
I'm sure there's some philosophy that says one of the best ways to deal with any of your problems is to take a deep breath and step away from them for a while, writing does this for me.
I do think it is important to look at the writing as a job though and to commit to it like you'd have to commit to a regular nine-to-five.
Besides the soothing effect it has, I think my favorite part of writing is being able to use my imagination and creativity to make new ideas and people and situations come to life.
I try to make the writing as regular and regimented as possible. I usually get up at around 5 a.m. and read what I wrote the day before. Some of the time, after I read, I think the writing's very good and some of the time I feel embarrassed by what I've written. You have to learn not to pay too much attention to these feelings.
Probably the only thing that isn't great is the time when I know I'm very close to finishing the actual writing of the story and I'm overcome by this sense of loss. I think it's because I know I won't be "talking" to the main character anymore, it's sort of like what you feel when you know a friend is moving away and you probably won't be seeing her again.