In showmanship, the judge is looking for a horse in good condition well groomed, and with appropriate and well-fitting tack. Where the work comes in is the training that goes into putting the picture together and making a good exhibition. The little nitty-gritty details can make or break your performance; things like hand position on the lead, your position relative to your horse (and vice versa), etc. There are some excellent threads in this forum on some of the more specific questions.
In halter, like pleasure classes, the focus is on the horse. If you're showing in an appy halter class, the judge will be looking for how closely your horse conforms to the breed standards for conformation, movement, etc. It's a good idea to do the same kind of polishing for halter as you would for showmanship, because it's harder to show your horse to the best advantage without the control that showmanship training gives. The art of it really comes when you can put everything together and be a "presence" in the ring.
A stubborn horse walks behind you, an impatient one in front of you, but a noble companion walks beside you ~ Unknown