Since you mentioned baltimore, you might be local enough to benefit from this information...
if you want to randomly practice your signing, and drink coffee (from corporate overloards), the starbucks on 21st and P street NW (in DC) has a deaf group that comes in every 3rd Friday of the month until it gets too cold. They're pretty friendly and are usually willing to show people mistakes or answer "how do I sign this" questions..
tootles.