I believe this is a painting with deceptively simple composition. It may seem that Matisse plonked things onto the canvas any old place, or that he painted the table first and then had to fill up the rest of the space with something. But look at the way the arrangement of the elements leads your eye around the painting.
In the photo I’ve marked what are to me the strongest directional lines, pushing your eye up from the bottom and back from the edges, around and around to take in everything. Of course it’s possible to see this in other ways, such as up on the right, then across to the left. (Though the way you read a painting is influenced by the direction in which you read text.)
Consider how he’s painted the various elements, which are reduced to outlines and which are given prominence. Notice that there are no shadows, but there is a reflected highlight on the glass. Squint at the painting to see the areas of light tone more clearly, and how create a unity in the composition.
You can't see it in the photo, but the outlines aren't painted on top of the red, but colors underneath the red showing through. (If you're working in watercolor, you'd need to mask out these areas, and with acrylics probably paint it on top given how fast they dry, but with oils you could scratch through to the lower color if that layer were dry.)
"Not only did Matisse flood his pictorial space with a flat, monochromatic lake at full saturation, swamping the studio’s oblique angle; in addition he treated everything three-dimensional as nothing more than inscribed contours. Meanwhile, the only objects allowed full color or modelling come across as conceptually flat by virtue of their being in themselves flat—that is the circular plate in the foreground and the paintings hung on the wall or stacked against it."
-- Daniel Wheeler, Art Since Mid-Century, p16.
