Some subjects are much better paid than others, so although you may love the idea of writing about travel (badly paid) a better bet would be a niche like finance (much higher rates of pay). Check out the Pro Blogger job board for high paid freelance writing jobs – other places to look might be Textbroker or you can look at the “gigs” section on Craigslist.
Jack up your prices. If you're providing a skill, service or product that is in high demand and low supply, and you're making the most of your time, you should be making good money. Unfortunately, there are many people who are too humble or fearful to demand that they get paid accordingly. It's the pushovers in life who get taken advantage of and exploited, so if you think you might be one of them, learn how to stop being a people pleaser. If you work for someone else, ask for a pay raise or get a promotion, and if none of that pans out, revisit your career options as described previously. If you're self-employed, the first thing to do is to make sure your customers and clients pay up on time--this alone can substantially improve your income. Check your prices and rates against those of your competitors--are you undercutting them? Why? If you're providing a superior product or service, you should be getting at least the average, unless your profitability depends on mass production, in which case you're probably making a lot of money and wouldn't be reading this article anyway!
Hold a yard sale. If you have a yard or garage and plenty of items to sell, you can have a yard sale as early as tomorrow. By advertising your sale on local Facebook pages and Craigslist, you can also skip the paid newspaper ad and keep all of the profits for yourself. If you don’t have time to price everything, try asking patrons to “make an offer” or grouping similar items on tables with an advertised price (e.g. everything on this table is $5).
Offer to watch children or pets. If you know anyone who has children or pets, you could easily begin a side gig as a babysitter or pet sitter. To let people know you’re interested, send out a group email describing your services, post an ad on Facebook, or tell friends and acquaintances about your availability in person or over the phone. You can also create a profile on a babysitting referral site like Care.com.
Prior to that group, they had an online community for teachers looking for lesson plans. That probably sounds pretty random, but it's crazy the type of communities you can build and rally people around. If it's something that you're passionate about yourself and you want to connect with others that have that same passion, then an online community is something you should definitely consider.
Become a moving advertisement. “Wrap” your car in an advertisement, go about your usual commute, and get paid monthly to do it. (Some car-wrappers in San Francisco make as much as $400 a month doing this, but of course this varies depending on how big a city you live in and when / how often you make your commute.) You can also get paid to wear a company’s logo t-shirt around (particularly if you wear it someplace conspicuous, like at your school; see ShirtsInSchools.com as one example).