"When you think about a cannabis product or service, it doesn't lend itself to all of your traditional types of advertising and marketing, not only because of legality but because you have a very curious consumer - we're going to make a gross generalization - who is 'clueless' as well," she told CNBC.com.

"So if you have a clueless, curious person, even if you were a cannabis enthusiast, how could you really be educated [about the product] unless it was part of your job or your life's passion? This combination – of clueless and curious - is very interesting because it lends itself to trial and that's what you want. People are willing to try and have varied experiences."

With legalization at state level come new products. Leafly is an app and website that lets people search their local area for cannabis dispensaries and buy smoking accessories, and claims it was on track to exceed 50 million page views per month by the end of 2016. Leafly is owned by Privateer Holdings, a group which has raised $122 million in funding. It also owns Tilray, which exports medical cannabis products from North America to the E.U.

Johnston, who got into the business having been "a cannabis enthusiast my entire life," says that avoiding clichés such as cannabis leaf, a cloud of smoke, or use of the word "high" on packaging will help attract new audiences.

Products will be successful – whether that be the plant itself, or as part of a food for example – if they are targeted carefully. "The trends are leaning towards use-cases specific markets – this is good for a concert, this is good for date night, this is good for Sunday morning," she says, adding that symptom-specific brands will also do well.

She cites Kalm Fusion – a company she advised – as a good example of a pain-relief brand that has avoided clichés in its marketing. Kalm Fusion launched in November 2016 and includes marijuana-infused popcorn, mints and melts, which are flavored strips that help ease pain.

Johnston also sees 10 to 15 entrepreneurs every week with ideas that range from frozen cannabis-topped pizzas to skin creams made with cannabis oil and non-plant products such as storage containers or "delivery" devices to help people inhale.

But she says to launch and market a marijuana industry product successfully, differentiation will also be important. "The newer brands are going to need to leapfrog over existing concepts that lend themselves to cliché and an older, even stigmatized perception and that is going to require risk, and by that I mean spending [on marketing].

"This is one of the most difficult and competitive spaces, and early on people have not needed to hit the bullseye on differentiation, but we are about to turn the corner and luck is no longer going to be part of your equation of success."