If you offer freelance services or have a physical services business, then creating a blog is a must. On your blog you can write about the services you offer and how they will benefit your clients. Importantly you can add a ‘Services’ page, outlining the services you provide, what they include, and any other important information potential clients may need. This is an effective way to promote your services, generate leads, and increase your revenue.
Better yet, you can even upload your own book to one of the world’s largest book sellers: Amazon. With Amazon self-publishing, you set the price, retain the rights to your book, and get access to Amazon’s massive audience. For every sale, you keep 70% with Amazon taking the remainder as a fee. If you want to get started, check out Leslie Samuel's great guide to selling eBooks online or follow Tara Gentile on CreativeLive as she shows you how to use your existing body of work to write an eBook within the next week. Who knows, you might just write one of the best business books of this year!
ThredUp. Their tag line is "secondhand clothes, firsthand fun." And they have to get their clothes from somewhere. Are you catching on? You are that somewhere. The website sells women's and kid's clothes (sorry, guys). You send your clothes in a ThredUp bag with a prepaid mailing label, and ThredUp will decide the value. They're looking for nice clothes and popular brands, and there's a fee if your items aren't accepted. So if you have clothes better suited for a yard sale, hold a yard sale. But if you have quality outfits you no longer want, ThredUp will probably pay you enough that you can buy new threads.
Oh, my! That is quite a comprehensive list of ways to make extra money. I think many folks are looking to make an extra buck – especially online. And somehow just because it is online, they think it should be easy as well. My experience is that most of the money making ideas are good but need persistence and follow up before they start generating serious coin.
Find a profitable niche. Starting with your interests, write down as many niche ideas as you can. Think about topics people might search online. Ideas include passions (like surfing or body building), fears (like spiders or speaking in front of crowds) and problems (like getting out of debt). Do keyword research to see it others are interested in the topic. Find out if a domain name is available that matches the keyword 100 percent. 
One factor that you must be aware of though is that Care.com is a peer-to-peer arrangement. That means that you will be in direct competition with other pet sitters in your area. You must price your services competitively in order to get business. Once you begin to develop a list of regular clients, you will be in a better position to raise your rates. This will be particularly true as you get referrals from those customers.
Running a coupons website can be very lucrative. Find a coupon niche, select a WordPress coupon theme, and then display relevant coupons on your site. When your audience uses the coupon codes or discount links, you will earn an affiliate cut for example you could set-up a site dedicated to iHerb Coupons or add a page to your website with Web Hosting Promo Codes. Coupon websites are quite high maintenance as they need to be constantly updated with new offers. However, if you build up an engaged audience and allow them to post coupons and discounts they have found themselves, then quite quickly your workload will reduce.
If you’re looking for inspiration, my friend Michelle Schroeder-Gardner of the website Making Sense of Sense has become the expert on all things affiliate marketing. Michelle earns more than $100,000 per month from her blog and the bulk of her income comes from affiliate sales. Michelle has had so much success with affiliate marketing that she even has her own course called Making Sense of Affiliate Marketing.