My local Craigslist.org is the first place I go to sell something. It's best for items you think will appeal to everyone (therefore justifying the smaller audience) and large items that can't be shipped. Craigslist.org is great for taking your yard sale items online for local sales. For example, a friend recently bought two fans from people that live close to him. These one-off type items do very well on Craigslist. Just remember to use common sense and be safe out there.
Another option is to take photos locally for homeowners. Many people don't have good home listing photos of the home they're trying to sell. If you notice, many of these pictures, aside from the ones done by professional photographers, have bad lighting, show clutter, etc. If you're good at taking pictures and have a nice camera, you might be able to sell your photo taking services to real estate agents or to people trying to sell their own home.
Whether you have a website or are still dreaming up ideas for a blog, you can also look into affiliate marketing. With affiliate marketing, you partner with brands and businesses within the content of your website. If you mention a product or service, you link to that produce or service using a unique affiliate code you received when you signed up for that particular affiliate program. From there, you’ll make money any time someone buys a product or service through your link.