Mane and Tail Brush

Tie up your horse
Before you start your horse grooming routine, it's best to tie them up to a post or beam to ensure that they stay in place. Even if your horse usually stays in one spot, they may shift their weight or move their feet during grooming, so it's best to take this precaution.
Try to tie their lead rope to somewhere that's above the height of their withers (shoulders) and only use a quick-release knot, also known as a “highwayman's hitch” (you can find an easy tutorial here from Animated Knots). Ideally, your lead rope should attach to a piece of baling twine, attached to the beam or fence (or similar), as in an emergency, should the horse pull and get spooked, the twine can be broken.

Clean your horse's hoofs
To start, you need to pick up your horse's foot so that you can access it with your hoof pick. Stand at their side facing in the opposite direction to them and adjacent to the leg you want them to lift. Have your hoof pick ready in the hand furthest from them. Run your other hand down their foreleg until you are cupping the hoof, and slowly lean in until they shift their weight, which hopefully causes them to pick up their foot. If this doesn't work, you can try gently squeezing the tendons above their pastern (the sloping part between hoof and fetlock).
Next, keeping the lifted hoof supported in your hand, use the hoof pick to gently remove any debris that is stuck to the bottom of their foot. Work from the back to the front, which will ensure you do not accidentally jab your horse's leg, foot, or yourself, and clean out any dirt from around the frog (the fleshy “V”). If your horse is shoed, pick around the inside of the shoe to remove any pebbles, or, if your horse is barefooted, clean around the area where the bottom of the hoof meets the edge.
When you've got the hoof clear of debris, take a moment to check for any signs of injury or illness. A common problem is thrush, most obviously signified by a dark discharge from the frog area. Inspect the wall of the hoof (raised edge) for any cracks that may need attention from your farrier. Then, you can gently place your horse's foot back on the ground and move onto the next one.

Curry your horse
With all of your horse's hooves picked and inspected, it's time to pay attention to their body. Start by using your curry comb to loosen the dirt in their coat. As you go over their coat, you should see dirt particles rise up from the skin for easier brushing later.
Begin on their left side, working from ear to tail, avoiding the head, mane, tail, and lower legs, and taking care when going over bony sections of the shoulders, hips, and legs. Use circular motions, applying gentle pressure to dislodge any unwanted particles. Should your horse flatten their ears or swish their tail, they're indicating their discomfort, so ease off and curry more gently. Use the opportunity to check for any skin lesions or wounds as you go.

Brush away dirt and debris
Now you've dislodged all the dirt from your horse's skin, it's time to brush it off. So, grab your dandy mane and tail brush and use short flicking motions to whisk away the debris from their coat. You'll need to cover the same areas you've just gone over with the curry comb, still avoiding the head, mane, tail, and lower legs. Begin at the neck and work your way around the horse, following the direction of hair growth.

Use a body brush to add shine
The last brush you'll be using on your horse's coat is the body mane and tail brush, which has softer bristles that are perfect for adding a luxurious shine. Thanks to this gentler touch, it's safe to use this brush on your horse's head and legs, though you might need to use a smaller body brush for the face.
Starting at the head, work your way along the body and then down the legs. Use long, sweeping strokes in the direction of hair growth to whisk away any particles left by the dandy brush and to smooth down the hairs. Take care to use shorter sweeping strokes on the lower legs just to make sure that your horse is nice and comfortable.

Pay attention to sensitive areas
After grooming your horse's coat, you'll need to clean the sensitive face and dock (under tail) areas. Use a dampened sponge or stable rubber cloth to gently wipe around their eyes, ears, and muzzle, taking extra care not to cause discomfort. It's also worth checking for any signs of eye infections, like excessive tearing, swelling, or redness, as well as checking your horse's ears for lodged dirt or seeds. Be careful when cleaning or handling the ears, as some horses are very sensitive.
Next, you'll need to wipe your horse's dock area beneath the tail. Be sure to use a different sponge or cloth for this area for hygiene reasons, and take care to be very gentle with this sensitive area.

Comb through the mane and tail
To get a flowing, shiny mane and tail, you'll need to carefully detangle and comb them. Begin by working through the worst snags in the mane with your fingers, getting them separated as best as possible. Then, use your mane mane and tail brush to straighten out the hairs, working on small sections at a time and from the bottom upwards. An effective method is to gently grasp the top of the area you're working on with one hand and run the brush or comb through the hairs with the other. This should avoid any tugging.
When you are doing the same with the tail, you need to stand slightly off to the side, pulling the tail gently towards you. This will ensure that you're out of kicking range should your horse get spooked. Depending on the condition of your horse's tail, you can also consider using a stiff-bristled brush to brush through the mane and tail.

Grooming gets your hands on your horse.
A good daily groom doesn't have to take an hour. If you do it daily, your average time expenditure should actually be minimal. But during this daily routine you have an opportunity to get your hands on every inch of your horse, and what better way to quickly assess your horse's health?

This is in effect what I do during a physical exam. Touching the animal tells you so much more than just looking at it over the fence. Is the horse sensitive in a particular area? Are there any weird lumps or bumps? Any rashes, scratches, or swellings? A good grooming session will let you pick up on these things before they become a major issue.

Grooming acts as preventive medicine.
A good grooming session increases blood flow to the skin's surface, massages large muscle groups, and daily hoof picking keeps the feet clean and helps prevent common hoof issues such as thrush, a bacterial disease of the sole. Horses out in the wild don't have this luxury, but they have each other, and mutual grooming takes the place of mane and tail brush.

When you remove a horse from its natural environment and stick it alone in a stall, you need to take on the responsibilities of herd mates for the health of the individual.

Grooming increases the human-animal bond.
True, there are some horses out there that don't like to be groomed. But the majority does tend to enjoy it and this is a great opportunity to bond with your riding companion. Engaging your horse in an activity where you are not requiring him to actually perform any work is a release from the demands we push on our riding mounts. This is your chance to give back and let your horse relax.
Quiet time with just you, your horse, and a mane and tail brush can communicate feelings of communal pleasantries that benefit both horse and rider. For those just starting a relationship with a new mount, this is a wonderful way to build a bond, and for those beginning training with a young horse, grooming can re-assure an anxious green mount.

Grooming can be more than a brush in hand.
Sometimes, if you don't have time to ride, a grooming session can substitute. Practicing some ground exercises such as lateral neck flexions or picking up hooves and doing some leg extensions are great equine yoga moves to help with flexibility and balance. Some people take the time to practice ground manners or teach their horses tricks. It's amazing what you can do with your horse if you only have twenty minutes in the evening after work.

Grooming is excellent exercise — for you.
So, this is a purely selfish reason for encouraging people to take the time to groom, but how many of you have worked up a sweat just brushing your horse? Working that body brush over the top line will definitely work your shoulders and triceps if you are doing it right! Who needs a gym membership when you have horses, right?