Do you enjoy fast food or going into retail shops? Many companies hire mystery shoppers to test the customer service of their stores. A common one is Subway, which hires mystery shoppers to ensure that "Sandwich Artists" are following all the franchise guidelines. If you have time and can travel to different places, this could be a good side hustle.
Be creative when thinking of ways to take the relationship forward. Some writers, including fiction writers, for instance, give away the first book of a series. Others offer their readers in-person experiences or ancillary products to their books, and these offerings end up bringing in more significant revenues than book sales alone could ever deliver.
In my (unpopular) opinion, getting a raise is harder than getting a promotion. Think about it from your boss’s perspective, would you rather a) pay more money for the same service, or b) pay more money for additional responsibilities. Alas, if you feel you’re overdue a raise, check out Dr. Randall Hansen’s article on Getting the Raise You Deserve. There are some really useful strategies there.
Robert said he did an average of 4-6 of these gigs per year for a while depending on his schedule and the work involved. The best part is, he charged a flat rate that usually worked out to around $100 per hour. And remember, this was pay he was earning to advise people on the best ways to use social media tools like Facebook and Pinterest to grow their brands.