So it is
best to start with the question: What do I want colour to achieve in my art work? For a visual impact use complementary colours or a sense of calm use analogous colours. In the print of mine above I have used hot red and yellow to contrast against the black.
It is worth going to a gallery for fun and looking at the different art works to guess how the artist have used colour and why. I have added a link to my video on the subject and some other useful links.