Use Shared Libraries to contain media elements common to several loaded movies.
Use font symbols to keep font data separate from individual movie files, thereby decreasing file size and download time.
When incorporating sound, use MP3 files, the smallest sound format, whenever possible.
Use symbols, animated or otherwise, for every element that appears more than once.
Limit the area of change in each keyframe; make the action take place in as small an area as possible.
Break larger movies up into smaller movies and join them together using the Load Movie action.
For better performance, avoid animating bitmap images. Use bitmap images as background or static elements.
Use the Bandwidth Profiler and the Show Streaming option to simulate the playback of a movie over different connection speeds.
Streaming performance of Flash movies can be enhanced by reducing the amount of information in the first few frames of the movie.
Using simple vector graphics will yield better playback than bitmap images.
Use the 'Generate Size Report' option in the Publish Settings dialog as a tool to help optimize movie playback.
Test your Flash movies early, often, and on all browsers and platforms that you anticipate visitors will use to view your site.
Flash movie playback can vary with processor speed; test the movie on computers of varying speeds.
Use the lowest acceptable bit-depth and sample rate for imported sounds in order to achieve the smallest file size.
Complexity can slow framerate, even if the movie size is small. Minimize the number of alphas, gradients, masks and tweens you use at any given time.
