It depends a lot on how good you are and how much work you are willing to put in.
If you are trying to sell to friends, family, etc. and network to others through them, then selling online is the way to go. You can use a site such as Fine Art America or Redbubble to set up a free and simple way to handle transactions, printing, framing, shipping, etc. Basically, they make it easy for people anywhere to view and purchase your art. These sites also have the capability to interface through Facebook, Twitter, and so on to help you advertise updates/announcements on new pieces and so forth.
It's free, because they make their money through value-added products and services. You get paid for your artwork, but they get paid for the printing, framing, and so on that people purchase with the art. They are basically providing you with a free, professional storefront in exchange for using your artwork to generate business for their printing/framing products and services, which your buyer needs anyways.
It's super convenient. I use Fine Art America, and it works well for me.
The thing you won't get is widespread publicity to shoppers and collectors out on the internet looking for art, even if they are specifically interested in your style or subject matter. To get this, you need to put in a lot more effort, which you are probably not interested in if you are only looking to make a little cash off a hobby. If you want to turn it into a full-fledged business, however, then there's a lot more to say about this.
I personally think the most productive way to sell work is though local and regional art shows and events. No sane person is going to buy an original for decent money without seeing it in person first. Many people who show up to these things are specifically interested in artwork and often out looking for something to buy, which most of your connections through social media are probably not. Once you go to the same event a couple times, you'll likely start to get a "fan club" of sorts that can become a solid base of repeat buyers for your work. These people aren't buying just to be nice and help you out, like your relatives might be.
At least in the U.S., every decent sized town has an arts community and an arts council that you can join to get into this environment. These arts councils vary considerably, but the good ones are indispensable. If you want to sell, this is totally the way to go.
Their international site is called Pixels.com, but it's the same thing.http://pixels.com/
I've never tried Redbubble, but it's very reputable.http://www.redbubble.com/
"It stinks to high heaven, but we learn from our mistakes and eventually we stop weathering the storm and start being the storm." --MisterPho