Still life ought to be easier than portraiture. Landscape takes the prize because there is so much room for unnoticeable inaccuracy.
Square up your lines. Make sure edges are parallel to the edge of the canvas. Any orbs, spheres, balls, circles should have symmetrical arcs.....loosen up and make sure the curves are smooth.
Why would this be without a background? Everything has a background. You have to have a background, middle ground and foreground.
The background can be pitch dark, bright white and any degree of light in between. It is still a background whether it has any patterns or objects in it.
When you paint the background make sure you include some color of your objects. The area where the background touches the still life subject should be softened. If it is a lemon there should be lemon color blended into the immediate area in the background around the edges of the lemon. This makes the lemon appear to glow in the light.
