It's been brought to my attention (it seems) that when one is making a teaser trailer, one needs to think about 5 things;

Budget; Pretty straightforward if I do say myself as everything costs, why should a trailer be any different? Have you got the money to endorse a trailer for a well-known blockbuster? Or maybe, considering your budget, you'll want to go for something a little more... affordable. Namely cheap, small budget films. Whatever your reason/target, know- that it'll cost ya!

Actor/Director; Usually when trying to get your target audience interested, trailers tend to have the names of the directors and/or actors involved in the Teaser. Most will know this technique as the 'star system'. Fans of a particular actor/directors work will blindly go to see and anything they release as they are an existing audience. This knowledge plays into a producers hands easily.

Sequel; Was there a previous film that is widely popular? If so then in retro-spect, a trailer isn't and is needed. It's needed to advertise to its fans that the sequel will be coming out. It's not needed, however cause the audience who liked the previous film will know what to expect and will show up at cinemas everywhere regardelss of a trailer.

Adaptation; This can include anything from books to games, media to non-media. It could really be anything one sets their mind on as long as there is already an existing product. Even TV can be taken into account on this subject.

Action/Adventure; These kinds of teaser trailers are in their own category. Namely because this genre begs for the largest budgets and biggest special effects out of all the genre's. This could easily be a problem for small companies who would regard this a huge risk.