Hire serious riders who are passionate about the sport. Treat them well, help them feel like riders not shop assistants by ensuring they are immersed in the local riding scene at grass roots, not just the race scene.
The weekend is for riding. If you open on Sundays your staff will hate you and treat customers accordingly. You'll end up losing customers and staff. Have limited Saturday opening so you and your staff can get out and meet customers in their natural habitat or at least have some part timers who can cover saturdays - the real riders won't darken you door over the weekend.
Have demo days.
As others have said, have a good range of consumables. Stock some mainstream brand bikes but don't forget the niche stuff - people will come to your store just to look at a bike they haven't seen in the metal and will probably buy something.
Create a vibe, a good mood. Make sure it is relaxed. Have a sofa and some flat screens. Allow your staff the freedom to talk and relax with customers. Keep any admin or managerial staff off the shop floor - they kill the atmosphere of a bikeshop for the customer.
Never make a promise you cant keep. Don't order something and lie about the arrival date. The customer will not be back.
Hire the best mechanic around and treat him well - he will ensure a loyal customer base for service work.
Keep a good range of clothing and protection.
Sometimes it's worth having a superior product with an inferior margin rather than an inferior project with a better margin.
And forget coffee. Beer is where it's at.