If the order of services on your public booking page, i.e. where your clients book online, are listed in an order which isn't ideal, the order can be forced in your service settings in Settings | Services, clicking on the service name and then the Show more button above your (first) location. See images below.
Change the value of List position to the order you'd like each service to be positioned in the list:
0 is the top of the list and higher numbers would be lower in the list. Identically numbered list numbers would be ordered alphabetically.