I now work for myself and have never been a manager but I've worked for salons with good and bad incentives so hope these ideas will help!
- regularly update staff with amount selling and targets etc. don't be pushy but the occasional bar chart/percentage figures help motivate
- offer £X towards a product/treatment in the salon or a free product treatment to the therapists that recommend the most X treatment/sell the most product between X-X (on a weekend? Over a month?)
- mild competition between staff can be good I think so again, offer something to those who reach a target/goal
- X% commission on retail sales (personally I would very rarely sell if I wasn't making commission)
- X% service charge given to therapists that complete each treatment.
I'd have a think about what your staff members want/get enthusiastic about, what you're willing to contribute and what the staff members moan about the most and then see what you can create from that info! Hope that helps xx