I've got an office and i've also got a shop front in another town, my situation is the office/workshop located inside a multi bisuness building (no road frontage, no windows, smack in the middle of the building) works quite well whilst we advertise we have a lot of loyal clients and word of mouth is very strong, this office is also busier than the shop front in a larger/wealthier town,
So unless you can cover large outgoings for a shop (i.e already have existing work) and have someone avaliable to you try to build business first work hard on promoting your business first.
Then find a location and spend a day there, sitting around (drink some coffee/ have a donut and don't look like a bum) watch who walks past, are they workers? benifit bludgers?, how many people go past in a day? where are they going?, what other shops/business are in the area and do they compliment your type of business,
Talk to the shop owners and ask them what their rent is, is businees good in the area, do they need computer help?, what type of customers do they get?, is there many burgs done in the area?, what type of security do they have?
Check for easy access to your location, can customers park right out front? where can you put signage?, what facilities are there
Hopefully by asking some of these questions you will be able to make a good decision and all will go well, so GOOD LUCK