Samuel Z. Arkoff was a producer of genre films in the 50s-70s and the creator of American International Pictures, his own distributor. His films include such 'classics' as I was a Teenage Werewolf and Blacula. I remember reading Roger Ebert's review of Arkoff's Q: The Winged Serpent, where this exchange between Arkoff and critic Rex Reed was recounted:
Reed: Sam! I just saw The Winged Serpent! What a surprise! All that dreck--and right in the middle of it, a great Method performance by Michael Moriarty!
Arkoff: The dreck was my idea.
I came across an old blog post from Bill Cunningham who reprinted parts of an interview by Julian Meyers from 1998 about the 'ARKOFF' formula. In it, Samuel Z. takes the letters of his last name, and details what makes a good B-movie. There is a lot of relevance for microcinema, and it bears expanding upon for those interested in making movies of a similar ilk (just try to avoid the dreck whenever possible).
'A' is for Action
Lots of people love action, and since were talking genre films here, you'd be wise to include some. This can be a tricky proposition for the micros, since it is much easier to write an action sequence than it is to stage one and make it believable. Hollywood has set the standard for action, but they have an immense budget for pyrotechnics, blank-firing weapons, stuntmen, and expert consultants. We can learn from them, but be careful that you don't try to BE them. You may bury yourself before you even start. Don't spend your whole non-existent budget on one sequence.
Action is an Element, Not Everything
One thing I observed about the countless On the Lot entries (yes, I entered), was that there were often action sequences that only served to pad the story. I can't count the number of shorts that featured people running for no reason other than to connect the setup and the punchline. I still believe in the 'sandwich' theory (which applies to features as well as shorts), dictating the middle of your film needs to be on par as your beginning and end. There better be a good reason for that action or you risk boring the viewer.
Too Much CGI is a Bad Idea
Computers are a wonderful thing for filmmakers, but where effects are concerned, less is more. I've seen some shorts that are obvious effects exercises, where the eye candy is put first in front of story and characters, and they quickly become boring. There is also a high risk of looking extremely fake with low-budget computery effects shots. Big budget CGI often looks goofy and fake, so what chance do you have in pulling off a cinematic illusion? Some suspension of disbelief is possible here, just don't use it as a crutch or as an easy way to pull off something fantastic you've written (rewrite instead!). You'll lose your audience.
Practical is Where It's At
'Practical' effects are those done live as the camera rolls, and are often the best ones. Granted, you can't really blow anything up on set (or can you?), but lesser effects (bullet hits, wind, fog, etc.) are great because you see what you are getting, and so do your actors. It's much easier to play off something that is there rather than reacting to a director barking "you see the monster! It's horrible but you can't tear your eyes away! Scream! SCREAM!" Be creative with your limits, and you'll be rewarded.
Please Be Careful
When staging action, always have some kind of safety measures in place. Even in the bigs people die or are hurt due to carelessness. If an accident ever happens on one of your cheapies, you can kiss your talent pool goodbye. Anyone in their right mind is not going to want to work on a dangerous set--especially for no compensation. Have someone around who knows what they are doing (a gun wrangler for example), and always practice discretion with hostile props. Informing law enforcement is a good idea, but this will increase the red tape during production, so be prepared.
Action can be a great asset to your story, not to mention wonderful trailer fodder. Heed Mr. Arkoff's advice and use it, but heed my advice and don't let it subvert the main thrust of your story. Arkoff didn't care about bad reviews (like Roger Corman, his films were critic-proof), but you should if you want to create buzz, and later sales, down the road.