Side hustles are all the rage these days, so it's not surprising to learn that more people want a piece of the action. In fact, in a survey of 2,000 workers with full-time jobs commissioned by Vistaprint, an online provider of marketing products and services to small businesses, 55% said they'd like to turn a hobby into a side business.

If you're eager to earn extra money, a side hustle is a great way to go -- especially since those surveyed added an average of $14,705.16 to their annual income as a result of that side work. Here's how you can start a successful side hustle and, ideally, join their ranks.

Woman typing on a laptop and taking notes

IMAGE SOURCE: GETTY IMAGES.

1. Find something flexible

There are two dangers in starting a side hustle -- first, that you'll sink so much time into that gig that you'll compromise your main job, and second, that you'll spend every waking hour working, thereby running the risk that you completely burn out. That's why it's important to find a side hustle that's flexible and one that works with your lifestyle.

For example, you might really enjoy caring for pets, but if you start a dog-walking service that requires you to commit to a number of evenings each week, that's hardly flexible. Imagine you're locked into a rigid schedule, and you're needed to work late at your primary job or attend a social event. Suddenly, you have a conflict and a bundle of stress to contend with. A better bet, therefore, may be to take on a side job that you can do where you want and when you want.

2. Choose a side business where there's existing demand

Your side gig won't be profitable if no one wants to use your services. When choosing a side hustle, aim to address an existing need you know exists. For example, you might really enjoy painting, but how many people are going to buy art from an unknown artist? And how will you go about safely storing the pieces you create but have yet to sell? On the other hand, if you live in a neighborhood with several schools, then chances are, there are parents around who are desperate for babysitters and that could make for a more lucrative side gig.

3. Always be marketing yourself

The more people who know your services exist, the easier it'll be for you to earn money. Therefore, make a point of exploring different channels for getting your name out there. You might advertise at local businesses, join a local small business network, or even promote yourself through social groups online. Also, don't hesitate to enlist your friends' help in drumming up business. In fact, one thing you might consider is a referral program, where you reward the people you know with gift cards or even cash for bringing in business.

There's really no such thing as having too much income, and a side hustle could be your ticket to extra cash. Just be strategic when starting your side business to increase your chances of success.