Learn to Keep Those Hands Steady at Home

Stand behind a chair or high table in a riding position: knees
slightly bent at 90 to 100 degree angle, head up, back relaxed but
straight, and fingers resting on the chair or table at elbow height.
Now rise and fall as if you were posting. Concentrate on keeping your
hands motionless on the table.

Getting Some Wear and Tear?

If the inside of one leg is getting chaffed check that you are sitting
square in the saddle. Check that your stirrup leathers are the same
length. Compensate for differences in leg length with a shim in your
boot. Most people have one leg longer than the other affecting balance
in the saddle. Chaffing on both legs means your legs are swinging.
Practice keeping your lower leg still and wear riding pants with
leather knee patches or tall boots for extra grip.
Secure Your Seat

You may already be familiar with exercises in the saddle and you
should be able to do them at the trot. These are easiest and most
safely done on a longe line. Try reaching forward and touching your
horse's ears, turn and touch its tail, bend to touch each toe and ride
with your arms out spread eagle. The exercises encourage muscle tone
and balance.

It's Not About Strength

Don't try to pick yourself up with your upper body. Your shoulders
should stay relaxed. There shouldn't be a lot of brute strength
involved in posting. A few muscles might start complain and you could
get winded. Horseback riding is exercise. It may look like sitting,
but then so does bicycle riding. Think of the balance and effort it
takes to ride a bike. What would happen if you were to stop balancing
and pedaling?
Go With the Flow

Allow yourself to be lifted by the impulsion. Some beginners bend
forward. Your back should be almost vertical, with only your pelvic
bones making the up and forward arc

Sitting trot always

Sitting trot always takes some learning to get used to. Have your
trainer put you on the lunge line at first so you don't have to worry
about your horse and can concentrate on your position. Start off by
posting the trot and get your horse into a nice easy trot. Try
lengthening your stirrups a hole or two to help relax your legs. When
you start to sit, think of reverse posting. Drive your seat down into
the horse on every beat instead of rising up. This will help you get
the feel for the rhythm.

Make sure to remember to relax your back, seat, legs, shoulder and
arms. Sit back a little farther and lean your shoulder back and open
them up. This position will help you to stay balanced at the sitting
trot. Try to really feel your horses stride and push down and forward
into the saddle with every one. Once you get the movement down you
won't have to drive so much. Make sure you're not pinching with your
knees or turned your toe out.

Shailesh bhai with Ride Saddle

Ride Saddle

http://www.robinsonsequestrian.com/saddles-tack/saddles/general-purpose.html

Once mounted,

Once mounted, place your palms on the pommel and push yourself up out
of the saddle, at the same spreading your legs in a wide "V". Lower
your seat back into the saddle with your legs still stretched and feel
the difference in your seat.

Next grasp the pommel (or a strap running through the "D" rings if
that's more comfortable) and pull yourself even further down and
forward into the saddle. Now you're ready to sit the trot, in
accordance with the advice given in other posts here.

At first aim for only a few strides before repositioning yourself.
Gradually add more strides, but always stop with the first bounce and
regroup. This will be easier on both you and the horse.

Stop as soon as you feel yourself starting to bounce. Once you begin
to bump with every stride your horse's back will stiffen in self
defense and the bouncing just gets worse.

Also, if you can borrow a horse who works through his back at the
trot, so that the motion is more longitudinal than up and down, you'll
find your "eureka" moment will come much earlier and more easily.

SUN RISING AT R.D.ZALA HORSE RINDING CLUB RAJKOT GUJARAT INDIA

SUN RISING AT R.D.ZALA HORSE RINDING CLUB RAJKOT GUJARAT INDIA

RIDER

You want to be sitting as deeply as possible, so do some stretching
exercises before you mount - particularly a sideways lunge, where you
start with feet apart and slowly transfer most of your weight to one
foot, bending the knee and stretching with the other leg straight. You
should feel your inner thigh muscles protest a bit. After enough
repetitions you should also feel as if your pelvis has spread a bit
wider.

Horses are more sure-footed

Horses are more sure-footed than camels. Although some people may
dispute this, there is no way that a smooth camel foot can have as
much traction as a horse hoof, especially on muddy or icy surfaces.
However, a camel does have one trick in precarious terrain -- it can
drop to it's knees and crawl over the steep spots. And the soft camel
foot is more environmentally friendly -- it will leave hardly a track,
where the sharp horse hoof will cut up the trail (by the way, camel
droppings are also more innocuous and less offensive to "non-animal"
people on the trail).