Hi, nice pic & colors!
If you use flash, you can balance ISO and aperture. Speed is not important, depending on the ambient light to get some background details. If you use 1/60 will get some details, but if you use 1/!25 or higher the background will be darker. Most importantly, always try to diffuse flashlight. It's a process, you may try different materials and methods until you find one that satisfies you. Also, avoid using extreme apertures (higher than f/16, depending on each lens), as you will start having diffraction.