Sommelier in a liquor store?!
I'm certified through The Court of Master Sommeliers (the only legit program, IMO, and certainly the most respected).
I don't see much practical use to a liquor store, other than educational purposes. I mean, a large percentage of somm training includes proper service, which will be a nonfactor in the retail environment.
Which program are you looking at? I can give you more thorough advice once I know the course you'll be utilizing.
"The world is your oyster" so to speak
In addition to fine-dining establishments large and small, sommeliers are also employed by hotels, casinos, resorts, cruise ships, country clubs and in many other segments of the hospitality industry.
Professional sommeliers are also teachers. They educate others by conducting classes, seminars, tastings and wine dinners in a variety of formal and casual settings. Some sommeliers also work as wine writers or choose to own retail wine stores.
In large hospitality organizations, there might be several sommeliers on staff that are responsible for specific areas including wine, beers, spirits and cigars. Smaller businesses would expect a single sommelier to handle all of these responsibilities.
Work environments for sommeliers are usually a pleasant combination of the restaurant floor, wine cellar, kitchen and office. In the highly competitive world of fine dining, restaurants may choose to send sommeliers as representatives to prestigious wine industry events, competitions and wine conferences.