Many people begin to play the guitar by learning a few chord changes to their favorite song. In fact, I learned this way. There are many things to be aware of while doing this. There are things to know and do that can make it easier, and guarantee you will have success. There are also many things that can go wrong, and guarantee trouble.
You should first understand that often the term "simple chords" is very misleading. Most "simple chords" for guitar require quite complex movements of the fingers, in order for them to get into the final "form" of the chord. In the following essay, I am going to analyze one of the most common chord changes, and one of the most misunderstood in terms of it's actual difficulty. I am referring to the chords G and C.
Let's look at this chord change from the viewpoint of the ideas outlined in " The Principles of Correct Practice For Guitar". And I am also going to use a real life example of a student of mine named Kathy. You will see many things in her story that will be true for you also, and the principles will apply to all chord changes, not just G and C.
When Kathy came for lessons with me, she had already been trying to learn the guitar for about 2 years, with a few different teachers, and with no success. She could struggle her way into a few chords, but watching her try to change them fast enough to do a song was an exercise in agony, for me and for her. Her case is a good example of how bad things can get when there is no understanding of the mechanics of playing and practicing, right from the beginning.
First of all, I needed to make her aware of how tensed up her left shoulder was as soon as she began to raise her left hand to the neck. This made her whole arm tense, right down to the fingers. As she tried to get in to the first chord, the fingers tensed up even more, and started leaning and pressing against one another, instead of having the proper space between them.
This tension of the fingers immediately began to cause a reaction in the rest of the arm, tensing up the large muscles of the arm and shoulder. All of this created a great feeling of discomfort, that Kathy had assumed is "just the way it feels to do a G chord."
This is a situation that happens all the time to beginners, and even to advanced players to varying degrees. I call this buildup of tension as the arm is raised and the fingers about to move lockup. That is, the fingers, hand and arm "lockup" with tension, and usually the unfortunate player continues to try to get them in position by working through the tension, trying to make the fingers perform while they are "locked up".
The thing to do is stop, go back into the position you were coming from, and begin to move very slowly, examining the fingers closely as soon as they release the first chord, and focus on staying relaxed from the shoulder down to the fingers, and staying that way as the fingers move to their new positions.
Now, you have to look at the whole situation the hand is in. For Kathy, her thumb was wrapped around the neck in such a way that there was no space between her hand and the guitar, so her fingers had a difficult time, not being free and relaxed, or having the room to move. By the time she got in to the G chord, she was holding on to it for dear life! Not exactly in a position to easily change to the C chord, which is even harder.
Then, as she began to pry her fingers off the G chord and go for the C, she did what many people do, she led with the strong finger, the first finger, that is, and smashed it down on it's note, on the second string, first fret. Now, she was holding on to that for dear life, with the whole arm, from finger tip to shoulder, knotted up with tension.
Next came the attempt to get fingers 2 and 3 into position, which was very difficult for her to do, and me to watch, as those poor, stressed out fingers did their best to do her will. By the time she got them in to position, somewhat, they weren't standing straight enough to allow the adjacent strings to ring clearly, one of the difficulties of the C chord.
So the net result of all this effort was the inability to change chords smoothly, and the inability to get the notes of the C chord out clearly once she got there.
Here are the steps I used to undo the knots of tension that Kathy had unknowingly created and allowed, that were preventing her from performing actions on the guitar which anyone should be able to do, if they approach them properly.
I really believe that without this approach, she would never have unlocked the tensions that were preventing her from being able to do these chord changes. This approach will work for anybody, and any chords. Try it, with these chords, or any other changes that give you trouble, or that you would like to improve.
All of the above can be seen as an illustration of the first two Principles of Correct Practice, stated in my essay, "The Secret of Speed". I will now add the 3rd Principle of Correct Practice:
"The fingers are energized by Attention, and moved by Intention."
I will elaborate on this later, but you should read and re-read the previous essays in light of these 3 Principles stated so far, and your understanding of them will increase, and so will recognition of their relevance to your own playing situation. And so will their usefulness. That is, by thinking about these things, when you practice, your practice will be more powerful, resulting in faster progress.