Up to now, you have probably been putting your fingers down one at a time when you play a chord, which is fine—it works—but there is another way, too. This is a more advanced technique which I have seen help a number of beginner guitarists. You will probably find it quite difficult to start off with, but once you get it, it will speed up your chord changes a lot.
Change is in the air...
The concept is pretty simple... all you try and do is form the finger positions for a chord in the air before you put any of your fingers down, and then put them down all at once. It is harder than it sounds (as you are sure to find out), but because all the fingers go down at the same time it can really give you a leap in your chord change speed.
You MUST START SLOWLY when you are learning this exercise or you might end up undoing some of your hard work in getting your chords sounding nice, as you will find that your fingers go down onto the wrong strings. Just do it slowly and try and get it right. Only when you have it right should you think about speeding up!
If you find yourself struggling you might find that it helps to put your fingers down in the reverse order from what you are used to.
Another tip is to try lifting and replacing the same chord, just so you get used to what the shape looks like in the air, which also gets you used to putting your fingers down all at once.
When you are playing songs you might like to keep using an anchor finger if there is one available. Most chord changes do not have one, which is why we have to learn ‘air' changes. More often than not you have to form a whole new shape, and that is where this exercise really comes into its own.
It is a tricky one this, but well worth it, and you'll find it really does speed up your chord changes with a bit of practice. It might well take you a month to start feeling that you are making progress, but it's worth it. One of my students said he used to practise making the chords changes on his arm while on the train and that it made a huge difference, so that might be worth a try too. After all, it is really just about getting your fingers to be independent and to do different things at the same time! Fun +
Good luck ;)
OK, time to do those one minute changes now...