A rule of thumb of what I use when collecting art is to look at sufficient art. Start by going to local art shows and local galleries. Don't dismiss going online as well...because although you can't touch the art or you are not in front of it physically, you will be surprised what great pieces you can find on sites like etsy and eBay.
Once you've seen some art, now its time to pay attention to your feelings. When you look at a piece find out if you have a feeling towards it. (I believe the feeling has to be joy or a sense of peace). I believe that the secret ingredient in a good piece of art is peace.
I believe that artwork should give you a sense of peace, and if you find that special art piece, artist, or artists you should move towards that; because you will end up living with the artwork! So, might as well be something that brings joy and peace to your space.
So there you have it! Go out there and start seeing and feeling!
Here's a video I did on the subject. I hope you enjoy it!