Usually, a video trailer includes plenty of gameplay footage, but with a text adventure game, it’s difficult to do.
I filmed a game trailer with a few friends with a budget of next-to-nothing, and sandwiched some live action footage around a quick montage of my actual game. I’m pretty pleased with how it turned out, and if you want to see what I did, you can find it on youtube:
Is the goal to market your game as an app purchase? Then it goes in the same path as (and, unfortunately, competing with) all the rest of indie game marketing. Send it to game news sites; find journalists and reviewers who have posted about narrative games in the past; see if any youtube-gaming communities are interested.
(No, my advice isn’t different from anybody else’s. I have no secret tricks here.)
I think that many people are attracted to IF specifically because it has a huge wealth of free games. I think most people get their app sales from those not familiar with interactive fiction. I think Choice of Games has had great success with this approach.