Despite this new found popularity, the sales of the comics themselves have remained relatively the same. The audience of the movies represents a virtually untapped market and it's clear that the comic companies are not applying marketing strategies correctly to attract people in this market.
When it comes to e-marketing, the current trend is to cater to existing fans. Ads are mostly placed on websites current fans visit or on the company's own website. To get to the potential market of the movie goers, the companies (particularly Marvel and DC since those are the properties being most adapted) could create a tie-in comic series to the movie adaptions. These could become special universes within the comic company's mythos (which is done quite frequently) and then the plot of the movies could be advanced through the comic medium, bridging the gap between sequels. The DVD releases of the films could contain coupons that would allow the customer to download an issue for free.
The problem with this is that digital comic reading is still in its relative infancy. Each comic company maintains its own proprietary reader, making it difficult (and expensive) for fans to enjoy stories from all companies. As a result, piracy is a serious issue and won't be solved until there's an aggregate comic reader (Comixology sort of solves this issue, but it has yet to catch on).
Should all of these issues be fixed and the solutions be implemented, the next problem is getting the word out. Because the new comic tie-ins are relevant to the movie industry, ads could be placed on film websites. Social media campaigns (such as twitter accounts created to give incremental updates on a film's status and production) could be utilized, as well as leaking details to mainstream media and having news outlets pick up the story.
Of course, all of this doesn't matter if the actual content of the comics themselves is poor. The comic industry has tried multiple times to attract new readers, most recently with DC's The New 52 and Marvel NOW!, but these efforts have been riddled with the same problems that have plagued comics for years: terrible concepts and writing, managerial meddling and favoritism, and sexualization and objectification of women.
The comic industry is largely considered to be a boy's club by people both in the industry and outside of it, which is a view that needs to die out. In order to increase readership, comics need to be written exactly like the best TV shows, movies, and novels are, having rich worlds with nuanced, realistic characters of both genders reacting to situations in a believable manner. It's only then that people will stop viewing comics as being only for the nerds who sit at the back of the classroom, giggling as they ogle the needlessly revealing and impractical costumes of the female heroes.
