What size is right for your space?
When choosing the size of artwork you want for your space I recommend looking using tape to mark the size you're thinking about on the wall.
Try different sizes until it seems right. You can also cut a large piece of paper or cardboard to the size of the canvas and tape it on your wall.
Should you use multiple paintings?
Consider if your space could look great with a diptych (two paintings) or a triptych (three paintings) where I paint the same design across multiple canvases or create separate paintings that complement one another. Some people choose one larger painting to fill their space or two smaller paintings side by side.
Remember, if you're choose a frame for your painting it will add about an inch to each side.