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. 
If you have an eye for design and some experience of creating websites, then you could offer your services as a freelance web designer. You will need to create your own stylish website, and have a few other projects that you can show potential clients to demonstrate your skills. You will also need to initially spend time emailing businesses to promote your services and find work.
@Philip Taylor I was merely using medical science as an example profession. It’s quite obvious that you don’t have any professional courtesy and downplay professions in which you don’t understand. Logo design isn’t just logo design. I don’t know what the profession of a public accountant entails, or a lawyer perhaps, so I’m not going to give advice on matters that I don’t especially have knowledge in.
Another way to utilize your talent and business skills is to run corporate workshops online. Businesses are always looking for unique ways to help educate their workforce, and if you can package your talents into a day or half-day long session, you can sell that to companies all over the world to make money online. Start by building a portfolio and then reaching out on LinkedIn to influencers at relevant companies to see if they would be interested in you teaching their team.
Another option that isn’t quite cash back but is along the same lines of “make money by saving money” — the Honey Chrome extension. Whenever you head to your cart to check out, Honey searches for online coupon codes or better deals from different retailers. That means no more wasted time Googling “[insert store name] coupon code” just to come up empty-handed. Honey does all the legwork for you!
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.
I think you can do well with this business if you start with people in your neighborhood and ask them if you can have an opportunity to perform this service for them. Word of mouth will travel fast if you provide a good value. I think the key to doing very well here is to package your service. For example, try to find a price that works for mowing, weeding and fertilizing altogether.
One of the cool things about Google AdSense is that it's so easy to get set up. If you have a blog or website, you can sign up for a free Google AdSense Account. From there, Google will give you a unique code that you will paste onto your website. Google takes it from there, tracking your page views, traffic, and earnings on your behalf. There is no upkeep or maintenance to get this thing going, which makes it a no-brainer if you have a website already.