Buy underpriced used books. Outfit a phone or PDA (personal data assistant) with a scanner, scan the ISBN numbers of books at used bookstores and thrift shops, and compare the asking prices with what the books are selling for on a site like Amazon. Whenever you get a good hit (which won't be often but, since the process is fast, won't take long, either), buy the book and resell it online. Be discreet about this, as the store managers probably won't like what you're doing.
These are the things you may get to your student e-mail inbox from your university or careers service every now and then. They aren't dangerous and usually don't require too much effort or time. They tend to compensate you quite well (around £10/hour), and they may even interest you!
According to recent stats we now watch more videos on YouTube than searches on Google. And with the recently introduced YouTube Partner Program you can now profit from making and uploading videos. You will receive a percentage of the advertising revenue collected per 1,000 views.
Also known as Multi-Level Marketing (MLM), this is a business model that allows you to generate ongoing income in two ways: by making a commission selling products and by recruiting other members who go on to sell. The later allows you to make money from the sales made by those you have recruited.
The trick is to find properties below market value (BMV) by avoiding estate agents and instead flyering your area with your contact details offering to buy houses. Then approach investors with a no-brainer offer to pass on the details of cut-price property in exchange for a % of the sale value.
Most cities will have monthly networking events for landlords and property investors. Track these down, sign up, put on your best suit and go along with lots of business cards. Or you could start on LinkedIn or even Twitter to build some initial contacts.