This really depends on your comfort level with working with color at this stage. I always emphasize experimentation and play as a component of your art making process. I advise artists to experiment in the beginning stages, when there is little fear of ruining or losing something. Play for 20 minutes, and see what happens. Try observing what happens with a color when used in conjunction with other colors.
Once you start to move forward with your painting, the most important things to focus on are design and value, always! As you add color, ask yourself, “Is this a light or a dark value?” or, “Which would be the most important aspect to pay attention to?” The other components of color are useful as well, and are dependent somewhat on what you want to do in your painting - like featuring a certain color, for instance.
All the components of color will become more noticeable as the artist develops. In the beginning, pay most of your attention to the value contrast of color as this affects your art the most.