Carl Sandburg

Arithmetic is where the answer is right and everything is nice and you can look out of the window and see the blue sky - or the answer is wrong and you have to start over and try again and see how it comes out this time.

Hammer down product fundamentals first. Make sure you've got something that works before doubling down on promotion and marketing. Create a groundswell of organic support, and only then leverage PR and advertising to spread the word.