a. Resolution: While exporting the final file in a video format keep in mind the resolution of the exported video. Full HD (1920x1080) is the much common ratio followed worldwide.
Size: Various file extensions will have different sized outputs. MP4 is the most sought after file format that allows good resolution and not very heavy files unlike AVI or Quicktime.
b. Composing and packaging: Make sure the video has the title of the work and credits to form a complete package.