It takes 10,000 hours of practice to become an expert at anything. This has been proven over and over again - sports, music, whatever - the 10,000 hour figure remains constant.
For some perspective on 10,000 hours, one year, around the clock, 24 hours a day for 365 days is 8,760 hours. So, obviously, you're not likely to become an expert in a year. So, if you want to go for something more reasonable, and become an expert in five years, you'll need to practice more than five hours a day, every day. You don't get weekends or holidays off. If you want to stretch it out for a decade, you'll need to practice about 19 hours a week - essentially a parttime job for ten years.
Obviously, becoming an expert in not easy. I guess that's why there aren't a lot of prodigys and experts in any field.
I've been thinking if there's anything I've spent 10,000 hours on this far into my life. The only thing I can come up with is writing. Working in my favor on that one is that I started keeping a journal when I was very young, so I got a head start.
What have you spent 10,000 hours practicing?