One who has introduced you to a guitar may have not told you everything about proper posture and hand positioning for the instrument. If you have just started learning this instrument, you are likely to be unaware of complications of improper posture and other bad habits related to guitar. If you are living somewhere in Brooklyn, you can join a guitar school in Brooklyn. Your good teacher will help you in achieving the correct posture and depending on whether you play with your left hand or right hand, you will learn how to handle the instrument.
Keep one thing in mind; don't ignore it. Many of the professional long term guitar players end up having nasty side effects such as shoulder pain, back pain, elbow pain, neck pain, arm pain, wrist pain, tendonitis, repetitive strain injuries, Carpal Tunnel Syndrome and more. Not all professional guitarists end up with booking a series of appointments with doctors. You can also prevent those injuries and health issues like those guitarists. And, this will also make guitar playing a lot easy and pleasing. Let’s see different positions:
Sitting position
Once you are in your chair, keep your back straight and put both feet on the floor. If you are right-handed, keep the waist of the instrument on the right leg. Keep the back of the instrument against your chest and stomach. The neck of the guitar should be horizontal to the floor.Don't use your left hand while supporting the neck of the guitar from leaning down. With your upper right arm resting on the upper part of the instrument, you can avoid this. It should be comfortable.
Finger placement and left-hand positioning
With your fretting hand’s thumb resting behind the neck of the instrument, place it between the first two fingers. All your knuckles (first, second and third) should be bent. Press down the strings using the tip of your fingers. Keep your fingers close to the fret but make sure that fingers are not placed on the fret. Avoid touching the fretboard and make sure that your fingernails are short.Right-hand position (Strumming hand)
Your upper right arm should be resting on the upper part of the body of the instrument. Your right hand should be comfortably floating above the sound hole. Keep your wrist, arm and hand relaxed.Strumming Technique
Professional guitarists are using several strumming techniques for playing the guitar. Let’s talk about the most common strumming technique.Placing and holding thumb against the index finger provides you with decent support. Your pinky, ring and middle should be slightly bent towards the palm of your hand. It should feel natural.
Down strum against all the strings using the nail of your index finger. Now up strum using the nail of your thumb. Playing with thumb and index finger separately will produce a more tender sound. If you want the sound to be more clear, you need to grow your fingernails a bit.