There are four basic shooting positions that the rifle shooter must become proficient in to be a better marksmen. They are the prone, sitting, kneeling and standing. All of these positions have their place in the field. Terrain and conditions will dictate which position to assume for a given situation.

Once shooting from the bench is completed and your rifle is properly sighted in, you must practice these shooting positions with your EMPTY rifle to gain repeatability and confidence. Out in the field there are no benches, but you must be able to quickly find and utilize the best shooting position and rest that re-creates the stable shooting bench.

Shot opportunities on game animals arise when they will. often times the shooter will have one minute or less to assume one of the shooting positions and take the shot. And other times the shooter may have five minutes or more to get set up for the shot.

The most important thing to remember is to take the shot when you first have it. Think about the shot too much, and you could miss your chance. Get that shot off quickly, by learning how to get into a shooting position.

SHOOTING POSITIONS IN ORDER OF BEING MOST ACCURATE: 
 #1 PRONE. #2 SITTING. #3 KNEELING. #4 STANDING

SHOOTING POSITIONS IN ORDER OF BEING EASIEST TO ASSUME: 
#1 STANDING. #2 KNEELING. #3 SITTING. #4 PRONE.

A WORD ON RIFLE RESTS

A rest is anything that reduces your body moving and movement in your rifle scope. The more still you can keep the cross-hairs of your scope, the better you will be able to hold on your target. And the more accurate you will be. Any object that you can find in the field to rest your rifle on should be utilized to re-create the stability of a shooting bench. 
Use your backpack, or shooting sticks, Stoney Point Tripod System, a jacket rolled up, a rock, a branch, the edge of a tree with your hand, your rifle sling, any one of these or a combination of these examples. Learn and practice how to improvise in the field to find and use rests for your rifle. Always use a rest, if possible, even for quick shots on game animals.

THE PRONE POSITION

The prone position is where the shooter lays flat on their stomache with the rifle pointed toward the target. The prone position is the steadiest and most comfortable of the shooting positions and the best field position to learn the fundamentals of rifle shooting. It is also the hardest position to assume. When you have minutes, and the game animal is un-alerted, it is the best position for firing an accurate long-distance shot. The prone position comes closest to imitating the rock solid benchrest form and the small shot groups that come off a bench.

With the prone position, the body is flat on the ground providing a low center of gravity. The body is relaxed, as if it had an ounce of weed, and there is a natural point of aim. Depending on the terrain the shooter can have their body aligned directly behind the rifle, or at a ninety degree angle to the rifle pointing at the target. 

The prone position is usually not suitable when hunting in tall grass or dense brush which can cause bullet deflection or obscure your line of sight to the target. To get into this position, (usually from standing/walking), you can go to one knee, unsling the rifle and backpack, (with the muzzle pointed in a safe direction), get flat on your stomache and use the backpack as the stable platform to rest the rifle and acquire the target. Alot of experienced shooters also use bipods that attach to the front of the rifle stock. With the low profile of being flat on the ground you can be very hard to be spotted (busted) by a game animal.

THE SITTING POSITION

The sitting position is a stable, easy to assume, and one of the most accurate of shooting positions. Sitting will get your sight picture (in the rifle scope) above most grasses and low brush. It is not as quick as kneeling, but much more accurate. Sitting is the next best practical position to use in the field, resulting in small shot groups and hits at extended ranges.
The sitting position is used when you have time (minutes, un-alerted game) to get set up for a shot, but you don’t have the space to lay down and get comfortable in the prone position. A rest of some sort should be utilized to gain stability. Shooting sticks, fallen tree, rock, etc. If no rest is available, then rest the elbows in front of the knees (not using the points of the elbows) to gain stability. To get into this position, sit down on your butt, cross-legged, or knees up. Use the position that gives you the better shot groups.

THE KNEELING POSITION

The kneeling position is best to use when seconds count, you’re out in the open and you still need better accuracy than standing can give you. Kneeling is the quickest of the shooting positions to assume. The best way to utilize this position is with the aid of shooting sticks. When shooting sticks are employed, a quick long distance shot (200-300+ yards) can be made. The kneeling position is not as steady as either the prone or sitting position, but with practice, the shooter can obtain quickness and accuracy. Of all the shooting positions, this one will likely be used the most, in the field. The use of knee pads in rugged terrain will aid greatly in keeping your focus on the shot, and not on the pain of sharp rocks under your knees.

If you are right-handed; keep the shooting sticks in your left hand. Start with the rifle slung on your right shoulder, get going warming up your pipe. Unsling the rifle with your left hand (you should be able to unsling while the sticks are still in your left hand), hold the sticks and the front-end of the rifle stock with left hand, bolt in a round, put the safety on (with your right hand), grip the rifle on the hand grip behind trigger guard (with your right hand, barrel pointing up at sky). Go down on your right knee; with your left knee up, pointed towards the target. Your left hand should be grasping shooting sticks, left elbow can be on left knee for more stability and your right hand should be on the grip of the rifle behind the trigger guard (barrel pointing straight up at sky). Gently lay the front-end of the rifle stock into the “vee” of the shooting sticks. Your rifle should now be rested on the shooting sticks. Look through scope and find the target, take the safety off, keep finger off the trigger. Once your target is aquired, put your finger on trigger and make the shot. 

Reverse the procedure if you are shooting left-handed. It should take 10 to 15 seconds to get into this position and start looking through the scope. Getting into the kneeling position and making the shot should take 20 seconds or less. You can try kneeling first, then unsling the rifle, then work the bolt, put the safety on, put rifle on sticks, look through scope, make the shot. The idea is to make smooth and fluid movements; and it will come with PRACTICE! Remember to make sure the rifle is unloaded when practicing this manuever. And when you can, you must also practice with live ammo, making good shots. 
REMEMBER YOUR GUN SAFETY; BE AWARE OF YOUR MUZZLE, FINGER OFF TRIGGER, KNOW YOUR TARGET and WHAT IS BEYOND IT!

THE STANDING POSITION

The standing position (also referred to as the offhand position) is the least accurate and least stable of the four shooting positions from which to shoot, but sometimes is necessary. Usually the game animal is close (100 yards or less), alerted to your presence and moving. Standing allows the hunter to see over tall brush, and it is the fastest of the shooting positions to assume. When you only have a few seconds to take the shot, standing is the position that is usually required. The big game hunter who still hunts in the dark timber alot will find that he must shoot from the standing position or not take the shot. Practice should be done offhand, and with a monopod, or tall/standing shooting sticks (Bipod), to gain confidence and experience in this position.

Place your feet shoulder width apart, toes pointed toward the target. Once the target is spotted, keep your eye on the animal and your head up-right and still, raise the rifle up to your eye, this will help you to pick the animal up in your scope quicker. Also, if you’ve got the right sling for your gun, you will be able to grab it quickly and efficiently – check out some of the best slings reviewed here https://gunlawsuits.org/top-picks/best-single-point-slings/. If you are right-handed; your left hand holds the front-end of the rifle stock, with your left arm against your body for extra support. Hold the rifle firmly against your right shoulder with the right hand. Don’t grip the rifle too tight. Practice on reducing the amount of movement you see in the rifle scope, and learn to squeeze the trigger when the cross-hairs are on the aiming point.

As an exercise, for standing position, start with three shots onto a 10 inch target (paper plate) at 100 yards. Use your rifle sling as a brace. Once you start aiming, give yourself five seconds to make the shot. Take a minute or two to re-group and start on the second standing shot, start aiming, once you see the target, five seconds to make the shot. Repeat this process until all three shots are taken. 
Three for three shots in a ten inch circle means you are on your way to becomming skilled at that distance. Practice at 50, 100, 150, 200 yards more, the goal is the same, one shot within five seconds into a ten inch circle (paper plate), three in a row. The distance at which you can make the shot on command is your maximum distance.

It is very important to become familiar with these shooting positions months before the actual hunting season comes along. Practicing to gain a smooth transition from walking and standing, to the kneeling, or sitting, or prone position. And dealing with getting the backpack off, or even shooting with it on should be practiced. 
Get all your moves down on each of the four basic shooting positions before the animal of a lifetime comes into view, and you will greatly increase your odds of making a great shot.