Break up your Flash file into many small movies
Load each movie separately so the main movie will load faster. Remember users are impatient.
Compress your FLA by doing a Save As
You can compress Flash movie by doing a Save As to a new file name. This will force Flash to rewrite the entire
FLA and only include the current data and assets from the movie and not the history. This can lead to strong FLA file size reductions.
Optimize sound audio
Use mono instead stereo. Event sounds are smaller, although one loses some flexibility with synchronization.
Use specific options to optimize speech, sound, music in Flash.
Convert elements into symbols and reuse it
If symbols are used repeatedly, symbols are loaded only once in the host's computer system.
Don't scale images within Flash
When working with image is to import the exact side they will be used in the Flash movie.
Avoid fancy font
Any fancy font you wish to display exactly on the user's computer. You have to set up the text as dynamic text.
This takes a huge chunk of file size.
Avoid gradients
Gradients increase the file size. Custom strokes also increase it.
Trace images instead convert
Shapes are heavier than strokes. Flash's trace bitmap tool creates two strokes for each line.
Trace image manually eliminates one stroke.
Clean up the library
Delete Flash movies, graphics and WAV audio's that are not needed.
Compress video as much as possible
Use Media Cleaner 5 to specifically optimize video.
Follow these optimization steps, you will have a great Flash movie.