So what constitutes a well-put-together hunter?
Your horse should be spotless. Give him a full bath either the night before or the day of your show. Any white socks should be bright white - not yellow or brown! If you have trouble keeping socks white, clip the white hair short and use a whitening shampoo on them the morning of your class. Make sure that the socks are completely dry before you put the horse anywhere dirty because any water will attract dirt!
If possible, have someone standing at the in-gate with a towel to wipe your horse down before you enter the ring. Make sure to remove any slobber that was produced during your warm-up and use a brush to clean any sand or mud off of the legs. Repeat after every round so that you go into the ring looking as clean as possible every time.
A well-braided horse will look more put together than an unbraided horse, every time. Use hunter braids (I have a post on them here) and either have them done by a professional or, if you decide to do them yourself, make sure that you practice many times beforehand so that they look acceptable for the show ring.
Your clean, well-fitted tack should look like it all belongs together. It doesn't matter if your bridle is made by a different manufacturer than your saddle is, but try to have the colours match as closely as possible so that nothing jumps out as not belonging. Medium brown and dark brown are less likely to draw attention when put together than a light tan and a dark brown would be. Also try not to use tack colours that will clash with your horse or that will really stand out to the observer. The judge should be able to easily focus on your horse rather than on your tack!
The same thing goes for any piece of tack. A fluffy, white girth cover will distract from your horse more than is necessary.
Fitting your saddle pad well
Your shaped white saddle pad should extend from the saddle evenly on all sides and shouldn't be so large that sticks out more than a couple of inches on each side. See this post for examples of well-fitting and ill-fitting saddle pads.
Using legal equipment
I will write a future post on illegal hunter tack, but it is always a good idea to check the rulebook yourself to make sure that whatever you are using is legal and won't get you disqualified! Make sure that you're using a regular cavesson noseband only and no horse boots or bandages.
A well-dressed rider
There's no point in turning your horse out well if you are going to look sloppy yourself. A sloppy rider will distract from the horse and that is the opposite of what you should be doing in the hunter ring. Read this post for tips on hunter rider attire.
Use hoof oil on clean hooves to finish off the look. Depending on which brand you use and how you apply it, you may need to re-apply the hoof oil after your warm-up and/or between rounds.
When you put together all of those factors, you will end up with a beautifully turned-out hunter!