Technical things like what editing software you use or what aspect ratio you shoot at really are only the smallest of parts that come into play when it comes to making a movie more cinematic.
Generally, here are some technicalities to consider when filming:
First of all, you will want to plan out your shots: this means you know beforehand how wide the angle of view will be (how zoomed in), how the lighting in a particular shot will look, how the colours look et cetera. This story boarding process is common in films, especially in cinematic sequences. Here are some story boards for The Magic Portal, without a doubt one of the best brickfilms around.
Then you will need to build the set and use the proper equipment. Obviously you are not going to get some good looking stuff using a cheap webcam and two lamps. I can't help you much further here except for the advice to buy a proper camera (either a webcam or a digital camera that can connect to the computer), lots of lamps (at least 4 would be nice) and build a smooth looking set. Another thing to consider is using lenses to adjust the field of focus; this way you can make the background look even more out of focus, for cinematic effect and such.
Of course, it all depends on every part of your film: not only the looks of the set, but also the script and how you turn your script into film, convincing effects (should you need any), sound editing, voice actors, music and all that jazz.