Hi, I like the simplicity of the render and the positioning of the main item. Also shifting the primary light color to a warmer tone might help. For the color from the background there are several ways to do it.
Go to the world tab and select New
Then you can head over to color to change the general color and strength to change emmision strength of the background
Or you can head over to the shader editor
Then click delete the default background node, add, texture, image texture, then use an HDRI map as the image
Also it might look cool to make the marble a little shinier, and dull it using a specular map for the material, or randomly using a musgrave texture