Nowadays with the resources on the internet it is very easy to get started playing guitar. YouTube videos, blogs, tab sites, and video conferencing all make it very easy to get started without a live teacher directly in front of you.
However, one thing that is pretty difficult to learn on your own is playing posture. I get a lot of students coming in for their first formal lessons who have been self taught up until that point, and usually one of their biggest concerns is whether their playing posture is correct. They are the smart ones, because they know better than to ignore it.
Your playing posture is something you should be concerned about. You may even have bad posture now, and not know because you are young or otherwise healthy and your body can take it. But as you grow older and keep playing with poor posture, it can lead to debilitating strain injuries like carpal tunnel syndrome or tendonitis, as well as other unexplainable fringe pains. It can also hinder your capabilities like speed, strength, and endurance.
Here are some general guidelines for playing faster, stronger, and longer:
-Stay fit. Overall physical fitness is a great and broad thing you can do to help your playing. It improves circulation, maintains muscle vitality and keeps your joints comfortable.
-Speaking of circulation, warm up. Especially when you come into my teaching studio in St. Paul from a cold Minnesota winter in the dead of January. You don't want to embarrass yourself or even worse, injure yourself.
-Keep your joints close to the middle of their range of motion. I'm talking about wrists mostly. Avoid sharp angles.
-Listen to your body. If you feel pain that lasts for longer than a day or two days, talk to a seasoned performer/teacher who has legitimate expertise on performance injuries, or better yet, a doctor or physical therapist.
-Take frequent breaks. If I know I need to practice for a long time, I usually set a timer for mandatory breaks, say every half hour take a 5 minute break. When the timer goes off, just drop whatever you're doing no matter what it is and go do something different for 5 minutes, preferably something physical. Go out and shoot some hoops, play with the dog, play catch with a friend. If you can't go outside, jog around the house, go up & down the stairs a few times, or just stretch.
-Sit up straight. This will do wonders for the rest of your body if you just take care of your central structure.
-Don't wear that guitar too low. You might think it's cool now, but you're not gonna look cool when you have wrist braces in ten years and you can't play in a band anymore. A good rule of thumb is to wear your instrument high enough so that the position remains constant whether you sit or stand.
Now keep in mind, if all these tips are new to you and you implement them today, it will definitely feel different. Some might say weird or awkward. This is mostly because you're just not used to it yet, but that doesn't mean it's not worth it. It would be well worth your time to visit an expert on the topic, have them observe your playing, and ask questions and invite feedback.