In the first two parts of this series (here and here), we managed to clear things out and determine a color palette. Now that you have a great base settled, adding the natural element will dramatically enhance your space. First, it shows that you are a responsible adult and can take care of something that's somewhat high maintenance (*ahem, see the exception below). Also, plants are a little unexpected. While you may be used to seeing a vase of fresh flowers, or the unfortunate elaborate silk floral arrangements that seem to hang around well after their lifespan and collect dust, plants tend to be a little more unique and free-flowing.
While doing some research for this post, I came across a great article on Lauren Conrad's site. It goes into how to plant for interiors, how to deal with dead roots, and other basic information for beginners. She also had this pretty illustration of the best plants to keep alive.
*Now, I say all of this with a grain of salt - I'm the worst of the worst when it comes to keeping plants alive. Throughout the past three years, I've killed about 15 plants. Finally I've come to terms with this fact and switched to faux plants, but it was really rough going there for awhile. That being said, I cannot give you any good advice for keeping your plants alive - you'll have to do your own research on that.
If you fail like I have (eventually I'll climb back on the horse for another go, but it's just too soon), find yourself some good looking faux plants. I suggest you stay away from ordering online, unless you have seen them in person first. Do your research. It's easy to find bad-looking fake plants. To help you get started, I am including a couple of resources that I've found.
The first three are from Ikea. They have decent faux plants at great prices. Make sure you look for good ones, sometimes they have been picked through pretty well. "Replant" them into a nice pot and you're good to go. The second three are from Pottery Barn. They are little more expensive but look really good in person.
Now, to further inspire you and prove why you need plants in your life, a little selection of some of my favorite rooms.