It seems to me that, when learning a new skill, there is often a “formula” or basic idea that, once mastered, provides a way into successful practice of the new skill. So here are 3 ideas for you to try. See if one of them helps you create designs that you like.
1. Use lots of “negative space”, and start by making this background space in a shade of gray. (The person who brought my attention to this “rule” of modern quilting has asked to remain anonymous 😉 ) Here are some examples, but I’m sure you know of lots of others:
2. Another common way to “design” a modern quilt is to make it an obvious take-off from a piece of 20th Century art (or occasionally more recent art). My design below is by no means an exact copy of any of Piet Mondrian’s work, but it certainly is an imitation of him:
Sometimes I do see modern quilts that are a direct imitation of an artwork. However, my preference is to look at a lot of work by one artist, or by a group of similar artists, then close the book and draw something original that “references” the works I’ve studied.
For example, here’s a print I found at an Etsy shop called “Handz”. Compare it to the quilt just below it. It’s not a copy, but it could have been based on the print. Or they could have both been inspired by another source altogether.
3. Just start with modern fabric. One of my favorite “modern” quilters is Rita at Red Pepper Quilts. Many of her quilts are traditional designs, but she uses bright, modern, fabrics and her quilts always look fresh and modern to me.

Spools and Nine Patch Quilt by Rita at Red Pepper Quilts
Here’s a detail of another of Rita’s quilts:
Give some of these ideas a try, and let me know what you come up with!
I’m not really “into” grey, so that isn’t a route I’m likely to take. However, I know I could be more creative in how I use space. Perhaps, that’s where my brain should work…
Thanks. 🙂
Thanks for reading! And grey is useful, but it’s been “in” a long time now. May be time to move on.