Know your products! What you have, how to use them and what the trade-offs are between the options.
If you don't carry it, know who in the area might carry it. Referring someone to an LBS besides your own shows concern for the customer. I understand this is a tough one, so...
If you don't carry it, know how to order it, and how long it should take to get it.
Don't treat someone as less because they don't like the same kind of riding as you do, and know enough about every kind of riding to provide a sounding board for your customer.
Don't look down on anyone because they don't lust after the latest carbon bling.
Be an advocate for your customers... whether suggesting the best product for your customer's needs (not necessarily the most expensive) or letting the manager/owner know what would be helpul to stock.
Learn to balance letting the customer know you are available without hounding them. Be casual but sincere in offering assistance.
Keep the sales floor uncluttered.
Serve customers in the order their need came to your attention, not giving preference to the one looking at the big ticket items... You can knock out a couple of small tasks quickly, and you will get to the big ticket item soon enough... If you have a second, remind him/her that you will be with them in a minute.
Drop everything to serve the VIP if a Cycling Forums member comes in...