Get as much footwork done as possible: business plan, operating agreement, financing, possible locations (with some lease negotiations thrown in), suppliers, providers, etc.
Always remember to hold your vision, ethics, passion, and humanity as close to you as possible.
Never let those bottom-feeders try to drag you down and attempt to hinder your ability to be all you can be.
You're going to hear all sorts of advice, probably most of them telling you why your vision is wrong or if you sold X product you'd make "millions".
The only sure-fire way in the coffee business to get out with a million dollars is to start off with five million.
You're right to feel trepidation at starting. In fact, you should be downright scared. The market hasn't been increasing much, coffee is at an all-time high, retailers are still reluctant/scared to price their offerings according to their costs, everyone has something to sell you and the rest want you to donate to whatever charity they're raising money for. Staff is continuously bleeding your costs, you're ready to default on your loan and all you really want to do is make nice cups of coffee for people and give them a place to hang out for a little while.
Everything will conspire against you. Prepare for it.
1. Be educated - Prepare yourself for everything possible from bookkeeping to being a negotiator/owner/manager/marketer/trainer/barista/plumber/dishwasher... Have a solid foundation before you start, or you are asking for trouble.
2. Be well funded. If you don't have $$$ yourself or from someone who loves you, you're not getting it.
3. Be bold. It pays to be daring. But it doesn't pay to be careless. (see #1)
My absolute number one piece of advice is to make sure you are not undercapitalized. Take your worst case P&L scenario and plan for 3-5 years to turn the corner. The leading reason for small-business failure is not having enough capital to weather the storm. If you don't have enough money to be open for at least two years, you aren't ready.
Get really, really comfortable shoes.