If you would be happy with 5 bookings a day and working 20 days a month, you only need 100 clients returning monthly to be fully booked.
Focus on client retention and word of mouth referrals. it's all about service and how your client feels. It's not really about an amazing technical skill - because your client will take that for granted.
Discuss your clients needs, ask how long her polish usually lasts without chipping, discuss aftercare, talk about her next treatment, get her booked back in. When she returns ask her if she noticed an improvement in the things that concern her - did the polish wear well, did she enjoy her colour choice, check the condition of her skin - better? issues?
Make notes so that you can develop a relationship with your clients. If she's going to an event, ask her next time how it went. Look after her and her nail needs.