In my personal opinion, it's really difficult to get a crisp, good quality haircut on a curly dog that isn't fluffed. This guy isn't fluffed quite as well as I would have liked because we have a new bather training with us, but I'm going to talk about some ways to work around this for home groomers or professionals in salons like petco which I'm told don't have stand dryers.
One way is to use a strong slicker brush (photo #4) to brush the fur up after the first time you go over it with your clippers, so that you can go back over it and get a cleaner cut.
Another way is to use a comb or blade that is 2 lengths longer than the one you're using and back shave to get a sharp look. (Photo #5 and 6). I used a 1 on his body so when I back shaved, I used an A comb because in order from largest to smallest, the combs go E C A 0 1 2 4 5.
Lastly, if you don't have a stand dryer but want to fluff the coat out better, take the nozzle off the blow dryer and hold it up against the dog's body and go slowly over each part.