If you have graphic design skills then you could make money online by creating and selling your own design elements, like templates, fonts, graphics, and other assets. This is a great way to earn extra money and build up a portfolio of work, which could lead to you picking up freelance graphic design jobs. Websites like Envato Elements pay you a fee per element sold, which can become quite profitable if your work is popular.
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.