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. 
While cryptocurrency is still relatively new, it will ultimately become the standard. Bitcoin and Etherium might be the primary cryptocurrency platforms today, but the US Dollar will eventually become the Digital Dollar by leveraging the blockchain. You can take advantage of the current boom in cryptocurrency by trading it through platforms like eToro and Kraken, amongst many others.
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.
It works essentially the same way as the phone apps do above. If you don’t care to let Google know what you do on a daily basis, you can make money from home by letting them monitor your Internet usage. They use the information they gather to help them market/increase the functionality of their advertising programs when targeting users that are similar to you.
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.
I’m a huge fan of blogging because I love writing and connecting with people all over the world. To give you an idea of what is possible with blogging, DollarSprout.com is part of a group of blogs that routinely brings in over $100,000 a month in revenue. While it takes time to build your blog up to that income level, you can get the initial set up done in under 30 minutes (no experience needed).