Is this the bedding you'll use? Generally, fabrics, rugs, etc are selected before paint which is the last step since it can be adjusted to work with the other non-flexible elements. Search the box above under Photos for gray headboard to get inspired, and consider starting with a rug pulled 1/3 under the bed as an anchor for the direction to go. Don't forget about a great light fixture.
https://www.houzz.com/photos/40-park-morristown-njroselandproperty-master-bedroom-contemporary-bedroom-new-york-phvw-vp~149738

Thank you, it is duck egg... white bedsheets yes, what a cream rug? or is that too bland?

I'd add a bit of pattern like the 40 park pic. Just enough to create some "movement" in your space.

One Houzzers "duck egg" is another one's ""aqua." Can't find a duck egg headboard for any inspiration.

perhaps grey damask background wallpaper? or plain french grey?

Thank you Thos. Baker, I like this idea using this wallpaper effect. What colour cushions would you buy other than blue?

Hi Danielle. By cushions, do you mean throw pillows on the bed?

Christi, on behalf of Thos. Baker

possible blend of headboard and wood flooring:

I think you need to find bedding that compliments the gray upholstered headboard. You need to find bedding that has a touch of gray in it or you could leave your duvet color white and add a gray coverlet at the foot of the bed. Also, you need to add art work over the headboard. Some tall bedside lamps would look great in your space. Good luck. Hope the attached pictures help.