My notes from the 20 tips and tricks session (attendance about 50 people) by Alessandro P (biskero), Darren O, Scott J, and Dale R.  I expect the slides to be available somewhere, sometime... as these notes are not always very clear :-)

• Make the app work first (before making it pretty) - remember to also add Exit button 
• Stay below 70% memory
• Remote Data and Flash Lite - remember data costs, name-value pairs are still powerful, remember getURL, 3gp for video and aac for audio, for FL 3 use flv, avoid using XML whenever possible for large amounts of data, SWX
• A challenge with Flash Lite and firmware updates, as there are differences between FL2 qand FL3 - WURFL (as you would need to know about which FL version you are running on)
• Optimize your loops - negative while-loops are fastest of all, avoid function calls in loop condition (instead run it once before loop if value does not change)
• Join the deprecation appreciation society - even though the some old FL1.1 functions are deprecated, they might still be faster than the new replacements from AS2
• Use the keypad on the phone for navigation (an remap your numeric keypad on the PC to "simulate" phone keypad, which is reversed, meaning 2 is up and not down... this means both device central and PC's Web browser)
• Test automation through Device Central- create a device set, and run the same test on all devices (you could also take a screenshot of every test run for examination)
• Remote on-device testing - leverage Nokia RDA and Mobile Complete by Device Anywhere
• Device profiling - test the devices with FPS monitors or use the Device Central profiling features
• Extending Flash Lite (will be available Adobe MAX) - possibilities: KuneriLite, Janus, Flyer, Sony-Ericsso's Capuchin, SWF2Go, there is also an article
• Business tip #1: Know where your content is going to end up,  regional differences, differences between manufacturers, etc.
• Business tip #2: Know the market - what kind of content is popular in your target markets?
• Business tip #3: Grab your customer in less than 60 seconds - spend time in making sure you get the customer to download your content, it has to stand out from the competition
• Business tip #4: Use Flash for its strengths
• Business tip #5: Becoming a mobile millionaire takes time