2.) SIZE - Figuring out the size of your coffee table, is really pretty simple. Don't let the size be under half the size of your sofa or over 3/4 the size of your sofa. Take a look at the illustrations above, it might help you understand what I am saying a little more. A whimpy little coffee table just makes a room sad and understated, while something too large does the exact opposite and they tend to hog up the space.
3.) MATERIAL - This is the fun one. You can really bring out your personality with coffee table. There are so many options these days, wood, metal, glass and fabric. Really think about the functionality of your room to make the appropriate choice. A room with lots of kids and pets is not the proper place for a glass table, something more sturdy is your choice.
Also, please, please, please I beg of you, do not try to match the wood on your furniture to another wood in your room. That is so, um, 1990's. Boxed set furniture is about as boring as your could be! Curate your look, mix it up. If you have a lot of wood, throw in a metal piece, or a painted wood piece.
Lastly, you can always have fun with fabric. Find a local upholstery shop and have them build an ottoman to your exact specifications that you need. You can really have fun with pattern and texture with this option. Also, if you have little ones, this is a great option, for no hard surfaces, while practicing those first wobbly steps.
Here are a few coffee tables that catch my eye and can get your wheels turning: