Design is a combination of style and taste. It's about how you use the space. It's a reflection of your personality and budget. To get started, you'll do a lot of research and ask questions. You'll decide where things go, what color they are, what they look like, how much they're going to cost, and who'll do the work. You'll take into a account that your house should still work for you 20 years down the road when you're a little older and not so spry.
The process itself is pretty simple; making it happen is the tough part. But the most important thing to remember is that there's nothing more satisfying and fun than turning an idea into a reality. And, like anything else, the only place to begin is at the beginning.