I won't rehash all that's been said before so here are some other things to consider:
1) Do not be overwhelmed, but be smart and think through everything. Read A LOT. Ask questions and seek advice from BYC and old-school farmers. Sometimes the answer is somewhere in the middle. Read The Chicken Whisperer or 4-H material for practical info in layman's terms. Be prepared to make mistakes. Take notes. And remember, no one knows everything; we're all learning.
2) Consider your seasons of the year. How will you prepare for heat, cold, rain, draught, and what will your chickens need from you during those seasons? Those answers will guide you in shelter, water/food, and breeds.
3) Go the extra mile in predator protection. Yes, you really do need to dig that ditch and bury your fencing curving outward. In the beginning and on a regular basis, look up, look down, look under, and run your hands along the bottom half of your fencing for any weak spots. Raccoons are the devil.
4) Start small and informal. Just a few chickens for eggs. I bought six leghorns for $3.00 a piece from a family-run feed store. I learned so much about what to do (give them a swing-its entertaining for them AND for you), and what not to do (Leghorns aren't exactly cold-hardy and their combs were frost-bitten one particularly hard winter). Hatcheries and breeders are wonderful, but at the time I didn't know any breeders and there wasn't a hatchery within a 5 hour drive. I would have had to buy 15 at a time and pay nearly $50 in shipping when ordering from a hatchery. Over $100 in just chicks. That's a huge investment just starting out when you could use those dollars building a solid shelter. Now, years later, I use breeders and hatcheries for chicks.
5) Find a local, chicken-keeping friend. I have two local friends who breed and sell chickens, and they have been a God-send when I've had a question, a sick chicken, a funny chicken story to share, wanted someone to go to a poultry show with me, or to lend a sympathetic ear when I've lost a beloved chook.
Be smart, and enjoy yourself!