Run it as an add-on to your home, and place an ad for roommates. You'll have potential customers in no time. If you host a roommate per week or so, they might bring friends and significant others by, which adds to the client list.
A retail lot is nice if you want to make some extra money on the side, but it'd take up the time you could use to just pull people in for their mani-pedis, and whilst you're doing them, customers would just get angry and leave, or buy things and leave (if you had help).
If you're doing it out of a community venue, perhaps making friends with the clients you pull in would help. Sometimes they'll invite you to their places and you can meet their families (for potential customers).
That's just the tip of the iceberg. What packs do you have?