Hmm, an artistically interesting thread for a change, well done!
I don't have any concrete answers for you though, as I don't believe there are any concrete answers. This is because suspense is a perception rather than a measurable quality, it's subjective rather than objective. The art of creating suspense is therefore the art of getting as many of your audience to perceive what you've done as suspense, which leads me on to ....
Suspense is created by suspending 'the moment'.
While true, this definition is too vague to be of any practical use. In fact, using this definition alone would be dangerous advice IMHO!
The complaint most members of the general public have regarding indie films is that nothing much seems to happen, they are just plain boring. Many indie filmmakers dismiss this opinion on the grounds that they are not making a blockbuster and don't have the budget for loads of high quality CGI, lots of big explosions or high octane action sequences. This dismissal is a serious mistake IMO, what audiences say and what they mean are usually two different things! On the one hand they might be trying to be polite/diplomatic and on the other, they don't have a deep understanding of film making and are unable to accurately analyse and/or lack the vocabulary to accurately express their response. While there are some cinema goers who are only interested in wall to wall explosion fests, I don't believe this is what the majority of general audiences are referring to when they say that nothing much seems to happen. What they are referring to IMHO, is not specifically a lack of physical action but a lack of suspense, resolution, pace and shape, all of which combine to make the audience feel un-involved, uninterested and therefore bored. If one were to accept this statement then the failure of most indie films is not because of a lack of a blockbuster budget but due to the indie filmmakers' inability to manufacture, maintain and resolve suspense.
Going back to the quoted definition, the problem is that just "suspending the moment" does not by itself create suspense, it's far more likely to just be perceived as a pacing error, as "nothing happening" and therefore boring. Suspense is a type of tension which is based on expectation and context and therefore starts with the script, carries over into the filming and is honed in post. A interesting example is Paranormal Activity, if one can accept/believe the context, that one is watching "real" home-made video footage of paranormal activity, then the film is packed with suspense and expectation. If one can't accept/believe the context, then nothing at all happens for long periods and PA is one of the most boring films ever made.
Another method of creating suspense is juxtaposition, juxtaposition or contrast of edits, angles and/or of the visuals with the sound (or music). Again though, there is the real possibility of this contrast/juxtaposition just being perceived by the audience as confusing or contradictory and therefore un-involving and indicative of poor storytelling/filmmaking.
And, before APE jumps in, SOUND can create a lot of suspension.
As suspense is a perception, sound is certainly a big player in it's creation and maintenance. However, on it's own, I don't believe that sound is a particularly good creator of suspense in most instances. Certainly sound can create and maintain suspense but it can only usually do so convincingly with support from the script, acting, visuals, etc. Sound design can greatly enhance and intensify what is already there or already implied but it's not nearly so effective if it's unsupported. In other words, IMHO it would be a mistake to forget about suspense in pre-production or when filming, thinking that it can all be created and maintained in audio post.
I'm looking forward to the responses of others and to maybe adding to what I've said above.
G