OP, I don't know how old you are, but how often can you come in an hour? How quick do you tend to come, or indeed, how long can you make it last?
Perhaps factor this into how long a booking you make.
And as others have said, plan out what you want to do, perhaps even try something different like the reverse oral/facesitting that Plan R suggested.
Do a trawl of WGs, take a good look at their profiles and see what turns you when you look at them. What do you imagine doing with them? Perhaps even check out some porn on X Videos, and put something interesting in the search bar to inspire you. Project that onto the WG you have in mind (obviously check she does whatever it is you have in mind).
Do the planning, build up the anticipation, check the WG's UKP feedback, make the booking, turn up and do the business.