Honesty, upfront brutal honesty, product knowledge or an uncanny ability to ask a supplier who may know, service and a clear understanding of what we want from each other.
My local shop is quite happy to fit items bought from the internet, he will try and price match or get close where possible and if he cant he will tell me upfront BUT I will always give him the option to price the goods. Of course he has explained if I buy off the net and get him to fit, I pay a little more for it as his profit is reduced by not selling the item in the first place. Often whilst his prices may not be an exact match but are close I will buy them off him to begin with. He obviously doesnt cover warranty on items not purchased through him but will often tune the items after fitting if required.
We both know what is expected in our relationship, I give him a fair go and Im honest about what I am doing, he in turn helps me where he can on either pricing or fitting and lets me know upfront what my costs are either way.
His service is perfect, bikes are always returned on schedule or parts arrive when discussed, unless something out of his control occurs (freight, out of stock etc). If something is going to take 4 weeks, I know that from the get go, not in 2 weeks time.
His take on the net is that it is here to stay and it is only going to get worse, so he needs to do something to maintain his business. He may charge for a few things which he previously hasnt but that is a direct result of his margins and profits being squeezed through the net. I understand that.
I also have a clear understanding of his policy on both items bought instore and items bought on the net. He doesnt advertise this, but if you ask and talk to him, he is open and honest. Some shops probably need to find out their stance and policy/procedures for it, so customers know where they stand.
There has to be give either way to reach a middle ground. Shops who dont budge (on internet prices etc) wont be around for long conversly shops that dont appropriately charge to assist on mechanincal installs, tunes and services, wont be around for long either.
I dont think DIY mechanics areas should be an option, just pay the mechanic and hourly rate or a set fee for installation (part dependant of course) and let the bike shop makes its money. As consumers we cant have everything.
I know my LBS doesnt say 'Salvation Army (charity)' on its front door and it needs to maintain profits to keep the doors open. I know I dont say 'sucker' on my forehead either, so we met somewhere in between and everyone is happy!
This my friend is exactly what I want from my LBS.