Focus on the surveys and offers at the top of the list. Here's a tip not many people know. CashCrate has a special algorithm that automatically selects the best surveys and offers and places them at the top of the list. There are several factors that go into determining which are the “best”, including payout, approval rate, and a variety of other factors. But all you need to know is that these surveys and offers are great, so you can do them in confidence!
Learn then selling guidelines. Each marketplace has guidelines that define what you can and cannot sell. State and federal laws also impact what items are prohibited. In general, you cannot sell alcohol, weapons, service contracts, animals or event tickets. Also, while not always prohibited, you may find restrictions on how you can sell items in some categories, such as art, gift cards and coupons. eBay, Craigslist and Amazon publish these guidelines on their websites.
Your niche doesn't necessarily need to be an area you're already an expert in. You can also choose a specialized area which you're enthusiastic or interested in learning more about.Think of Oprah, she doesn't market herself as an expert, but she frequently brings other experts on her show. You can do the same in your niche, by giving other experts a platform to promote themselves in exchange for content creation.