The most challenging thing about playing guitar, no matter how long you have played, is changing chords smoothly and in rhythm. Even the greatest guitar players in the world struggle with a difficult chord change from time to time. But there are a number of things you can do to keep the music flowing.
Plan ahead. It's very important to think about the next chord and how it is played. In other words, make sure you know what fingers go where and where on the guitar the chord is played. In fact, try to picture the next chord in your mind. It will help you get there quickly, smoothly and cleanly. The goal is to make the chord change without interrupting the rhythm (taking too long to make the change).
It also helps to decide which finger(s) of the chord will land first. There are times when you'll be able to land all your fingers at the same time and that's ideal but not always possible. When playing a C chord, for example, it might be best to let your ring finger land on the 5th fret first as it is the bass note of the chord and the first string to play when strumming. Then quickly place your fingers on the remaining strings.
Substitute a different chord for a bar chord that's difficult to play. Even if the bar chord sounds better, if you can't make the switch in rhythm, you won't be able to make the song work (and that can be frustrating). With a little bit of practice and planning, you can play most songs without bar chords. When choosing an easier chord, keep in mind that you don't have to play all the strings all the time, In fact, for a lot of songs, many of the chords will sound better with three or four strings being played.
Make the chord switching part of the music. This is a little trick that all great guitar players know. For example, while switching from a G chord to a C chord, you can play an open string as you're changing. In this case, you could play the G chords three times, then play the third string open as the fourth beat while you are forming the C chord.
Use a bass run between chords. Try this one: play a G chord, then play the fifth string open, then the fifth string at the 2nd fret. Finally, play a C chord starting with the fifth string at the 3rd fret (the bass note for the C chord). Not only does it make the chord change easier but the bass run adds to the music.
Practice the difficult chord changes separately. Take the most difficult chord changes and practice them over and over until you get them down. The next time you play the song, you can breeze through the difficult parts.
Changing chords on guitar is a challenge for any player but there are a number of things you can do to go from chord to chord without stopping. You'll keep the groove going and sound great in the process.