The artist within you may be tempted to think that creating a script with the word “marketing” in mind is a despicable sell-out, but I can pretty much promise you that every studio movie ever made was made with marketability in mind. Every time a film studio (big or small) makes a movie, they do so because they want to have a product to sell; the decision to make a movie is a business decision, not an artistic one. And sometimes these movies suck, while other times – they rock!
The difference between suck and rock has nothing to do with the studio's marketing plan or the decision to make a marketable movie, but it has everything to do with the script – the film’s blueprint. The point is this – you can make a business decision to create a marketable movie, but every decision that follows must be an artistic one, and that is where your movie is made. Don’t shy away from making films about subjects that are easily marketable. In fact, I’d encourage you to keep your film’s marketability in mind while you write it. Check out my take on Being Economical when writing a script. The earlier you can think about how your film is going to be sold and marketed when it’s complete, the better. And once you make a business decision to create a marketable film, tell the businessman within you to buzz off for a few months while the artist within you writes the script.