The most important rule is that, as the economist Hal Varian says, “the product that people expect to win will win.” Consumers know that if they back the loser in a standards war they’ll be stuck with an obsolete product, so convincing them that your product is a winner is essential.
Once the public buys one of the products to the point of a majority, it's pretty much over for the other. And the public won't be doing that based on heavy technological analysis; it will be based on who is make the better argument.