Great job on this quilt - I love all the colors!
Another good way to choose colors is to pick a main fabric with a colorway that you like and pick out fabrics colors from this central fabric.
Great suggestion! I made a wall quite a few years ago that was 5 main squares and then a border. The pattern was from a magazine and they gave you a pattern per issue. It wasn't until the last issue when you were supposed to put the whole thing together that they gave a simlar suggestion - pick the border fabric (which is quite wide) first and then match the other fabric to it. Kind of late when the rest of the quilt was already done. So, I took my squares to the local quilt store and the fantastic owner was able to find a border that matched the colors I had used perfectly. No one would know it was purchased later!