Keynote Essentials

1. Use the document format that is more open and works better with version control 
If you check the preference to make new Keynote documents as packages, Dropbox, GitHub etc. will work much better. Behind the scenes, this means that instead of any change, nomatter how small, requiring a complete re-load of a monolithic binary file, instead the document is really a folder full of bits and bobs, and so version control can control the individual bits and bobs. Much better.
- Preferences > Tick "Save new documents as packages"

2. Ensure the right pixel size for print work
Long story short the best strategy with Keynote'09 is to put in 300dpi values for the slide's pixel size.
- Portrait: 2480 x 3508
- Landscape: 3508 x 2480

3. To get transparent backgrounds, set the slide background to a solid colour and then in the colour picker set the opacity slider to transparent (left hand side). Choosing 'None' as the background doesn't seem to work any more.

4. To export QuickTimes for video titles etc., you need to 
a) use 'Fixed Timing' instead of 'Manual Advance' or whatever else. Any other option will cause you grief down the line.
b) to export with transparency, you have to tick the 'Use transparency' box at the bottom FIRST, before setting your custom export format to something that supports transparency. I suggest PNG with 'Millions of colours+' set or ProRes444 (not 422).