I have made one bargello quilt before using a pattern and read some articles about designing them, so just dived in boldly. I really like the way colours can be used in this style and also that they look much harder to make than they really are.
First steps - good old cutting and sticking. Handily, Hobbycraft sell pads of paper with lots of shades of one colour. I used orange and blue cut into 2cm strips and glued them horizontally to white card, grading them from light to dark. NB I usually use inches for patchwork but swopping to metric measurements is an easy way to make a design to scale. So if I have 2cm paper strips, I know I will need fabric strips that are 2" + seam allowances.
Then I cut the strips vertically - this time I varied the width, starting at 1cm and going up in increments of 1/4cm - and spent some time rearranging them and seeing what patterns emerged. At this point it is useful to label the strips so you don't have to keep checking the size.
After a while, I realised I needed a lot more strips to see the whole design, and also to be able to compare different versions, so it was time to go digital and start to work in Illustrator. I will tell you how in the next post.