I used to own a golf shop in Bristol and was very customer orientated. My advice would be free coffee, a place for people to chat and mingle is invaluble, the longer there, more likely to spend. Always be friendly even when you dont want to be, try to remember peoples names/faces, goes a long way. The pump is a good idea. I used to sell lots of second hand golf clubs, one thing to be wary of is the VAT content. It is different with second hand goods, ie you only pay vat on the profit. So you will have to make a note of each bike bought, what you paid and what it sold for and pay vat on the profit. Its a pain in th arse but the vat man is not to be messed with!! Try not too spend tto much on advertising to start with, find your market, advertise with the local schools, college, uni's etc. You will make far more money on accesories so make profit but dont get greedy! People always like a bargain! Also, if you can do small repairs wjile people wait rather than book it in, that goes a long way aswell, the amount of people who wanted new golf grips while they waited was massive, they were always impressed and nearly always bought extra things while waiting! Obviously you will have to gear the repair man up for that!
Oh, dont be shy on securing the place, the reason im not in my shop now is 8 burglaries in 6 months, insurance only paid up for the first one! lost business / house in the end

Cant think of anything else at the mo!