I'm on the verge of rendering an after effects project that is absolutely massive, and I intend to upload the finished movie as my video presentation for a kickstarter campaign. Needless to say, the file size needs to be small enough that people will be able to load it on their devices relatively quickly. Of course, it also needs to be large enough to exhibit a certain level of quality.
My question: Is there an art to video compression (i.e. are there tricks/codes that go beyond what after effects offers for final render)?
My first suggestion would be to render to a lower resolution because it seems that most Kickstarter videos are in some form of SD. Secondly, consider simply editing down the length of your video. My third suggestion is to never render to a delivery format (h264) straight from After Effects. First render to an uncompressed or visually lossless codec, then encode your final video using Media Encoder/Compressor.
From After Effects I render to either a TIFF sequence or to AVI with Lagarith Lossless Codec (Windows only). Then I encode with ffmpeg/x264, which gives high quality and smaller file sizes, but has a significant learning curve and will require some research. Like with most things, do the research and do your own experiments to find what works best for you. Video compression definitely requires finesse and there isn't a single magic solution that will work for everyone, for every application.
Here are some helpful links to resources that I use in my workflow.
Most video hosting sites also recompress your video into several different versions that are then selected in real time for viewers based on device and network speed. Since it's likely going to be recompressed anyway, I would export with as a high a setting as your video host recommends (Kickstarter in this case), and then let their infrastructure take care of the rest.
I agree with Peter that it is best to export a high-quality master, because then you can use it to make different versions without having re-export it from After Effects or whatever software you may have used.