As stylists, we always try to start with the art, and then work back from there.
It's so much easier to put a room together working off the artworks, than to create a great colour scheme and try to find art that works.
Find your 'star' piece/s, for your most prominent wall, then search for your support pieces. They can coordinate colour-wise, or by shape/size/style, or by contrast - it doesn't matter as long as they somehow work together and tell a story that makes sense and means something to you.
Later, once you've pulled the room together, you will see where some extra pieces may be needed. These can be assorted black and white photos, or travel pics and artefacts. Usually things you already have, that you would like to display, or that need a home.
Take your time and have fun, selecting art is a hugely personal thing, so savour the process. Visit local art galleries and markets, or hop online. You can also hire original artworks, which allows you to try-before-you-buy. Or better yet, grab some paint, canvases, and a little inspiration, and have some fun!