At my marketing agency, Ciplex, I deal with a lot of clients who hire us to build a website for their business idea--based solely on their gut feeling that idea will be successful. They skip the step of figuring out first if they're solving a real problem in the world.

Big mistake.

Before investing any time and money in a business, you need to validate your idea. I asked members of the Young Entrepreneur Council, an invite-only organization for young, successful entrepreneurs about the best ways to validate ideas. Check out their responses below:

Use smoke tests.

An easy way to gauge interest in an idea is to run some basic tests fist. Devesh Dwivedi, an author and speaker who founded his first company at age 14, advises entrepreneurs to run a basic Craigslist ad to gauge interest. For example, perhaps you want to start a business around hiring babysitters online. First, place an ad that offers the services. Do people contact you? This is a cheap and effective way to glean feedback on start-up or related ideas.

Travis Steffan, a serial entrepreneur, says he generally places an idea on a site like LaunchRock, which helps people to quickly set up a "Launching Soon" page. He then invests in Facebook ads and watches click-through rates. If a good number of people sign up, it means there's real interest, and it's time to take the next step.

Assess yourself.

This one sounds basic but it's worth remembering. Instead of focusing on building products that are simply "cool" or "innovative," ask yourself if the product is something you would use. This is the approach Matt Ackerson, founder of SaberBlast.com, took when launching his company. The easiest way to validate an idea, he says, is to first "survey a market of one: yourself."

Find a mentor or industry advisor.

There are always going to be people who have expertise or experience you lack. Don't shy away from them--introduce yourself and make a connection. That way, you have a valuable contact in the industry of your choice to determine where the needs are, and how you can address them.

Conduct a survey.

Sites like SurveyMonkey.com can help you gather feedback on your ideas. Create one and share it on your Facebook page, Twitter feed, and LinkedIn profile, or send it out to trusted professionals, friends, former co-workers, students, and family in email blasts. This is another great way to gauge needs, interest, and gaps in specific industries.

Trust your gut.

It will lead somewhere, says Corey Blake, a comic book pundit and performer. Maybe it results in a successful product, maybe it won't. Either way, you get a valuable education in what works that will help you later on.