Here is a great article on what it takes to be a web designer, and insights into the career / lifestyle aspect. This should be required reading to anyone who is looking to get into the business.
Many of the principals discussed can transcend into other careers, such as taking criticism constructively, learning patience, being a helpful member of your business community, and believing in yourself. That is great advice not matter how you earn a living.
Balance is also important to avoid burn out. Take time for yourself, and time to spend with friends and family and enjoying life away from the computer. You don’t have to check into every location on foursquare, or update your status every time you leave the office. Unplug and refresh. In my experience, I feel more focused when I don’t burn the candle at both ends.
The most important principal covered in my opinion is to never stop learning. Think you know it all… wait until you don’t get the account after your next new business pitch. We need to say focused, stay hungry and stay informed. If you are not on top of your game, someone else is – and they are one lunch meeting away from taking your account. The best solution is education. Never stop learning.