Don't concentrate on your timing , concentrate on doing the best nails possible and your timings will automatically improve as you do more nails.
Having your station very organized is the biggest help, do you lay everything out in order that you need it so your never looking for anything you can just move on?
Do you keep your head down chatting, looking people in the eyes while chatting is great but will slow you down a lot!
I used to take about 2 hours to do this, I now take about 1hr 15min, to 1 30mins depending on the client. I don't do a lot of enhancements anymore, it seems to be all shellac at the moment, but at christmas time I can do them in an hour because i do so many sets in row ( I've about 7 years experience now with enhancements).
I use well less tips and never rush putting the gel or acrylic on, i take my time and try to get as perfect a shape on them as possible with the brush so that there is minimal filing to do afterwards, this is really where most of your time goes i would guess
If your really serious on wanting to improve your nails you need to buy and read nail class by gigi rouse, it's not expensive and will be the best investment for acrylic nails you've ever made, It goes through everything such as brush angles , mix ratio, finish filing …. everything to create the perfect set of enhancement!