What NOT to do - Avoiding 'download mode'??

[blueglide]

My PPC6800 is not in download mode and I'd like to keep it that way. But there appear to be more and more posts from folks here and on xda-developers that have 'bricked' phones due to a possibly incorrect flashing procedure. As best as I can tell from reading many of the posts it occurs when attempting to revert back to an older rom but thats where the confusion for me begins. I'm not sure whats safe and whats not. ImCokeMan has been very informative and speaks from experience with two 'bricked' devices but his posts have been individual replies and are scattered among many posts with different titles. I am hoping some of the more tech savvy folks here can explain what is known so far and what can be done reasonably safely and what to absolutely avoid. There are bits of information here and there but perhaps a 'how to' compilation (maybe even stickied) would prevent further 'bricked' phones and give some warning guidelines to everyone flashing their devices. I try to read and search everything before doing anything with my phone but I am no 'tech' guy so I'm hoping those here can lay down some guidelines. Thanks

Mods: Hope the title isn't misleading...if you feel it is please retitle appropriately.