In any key the three primary chords can be played in any order and they will always sound great together.
If you are trying to write your first song or work out some chords to strum along to a tune you have written then this is a good place to start.
Here we are taking the I – IV – V (or one, four, five) chords in a few different keys to get the idea.
So in the key of G try, G C D7 and then back to G.
In the key of A try, A D E7 and back to A.
Or in the key of E try, E A B7 and then back to E.
All chords from the basic set of open chords in a previous post.