Let me set the stage for you: 25 people have been wiping for over 3 hours on Kael'Thas. Tempers are high, and patience is running low. People are consistently dying over the same mistake again and again, and there is no end in sight. But wait! You have a suggestion! With this suggestion of yours the raid is sure to get over this minor roadblock, and progress to the next stage of greatness. Now comes the hard part...
How do you get your idea to the raid leader?
While often times it'll depend on what type of raiding culture your guild has, there's a few basic rules to follow.
First, never blurt a strategy out during the middle of a fight. If your guild is cool about talking out strategies over vent during raids, wait until the wipe is over to mention something. A lot of other folks are usually busy with things, even if you're dead (well, perhaps they're not busy enough!)