The secret to great marketing isn't really a secret.
The problem with a lot of marketing is that it tries to say too much, and it ends up saying nothing. Good marketers figure out which market is uncontested and which aspect of their brand story is the most compelling to the market. Then they create simple messages that communicate their brand story, and embed those messages in the minds of their potential customers.
Most marketing literature over the last four decades revolves around this single topic. Al Ries & Jack Trout called it Positioning. Seth Godin referred to it as the Purple Cow. The Harvard Business School said it's not marketing 101, it's advanced business strategy and they rebranded it the Blue Ocean Strategy. The HBS even created matrices and strategic frameworks (complete with acronyms) to make Blue Ocean Strategy appeal more to analytical thinkers. But, these books pretty much all say the same thing. They say the key to growing your company is to find an uncontested market space, create a simple message that communicates that fact and own that market space in the mind of your consumers. And they're right. That's the secret to great marketing.
But, what makes marketing hard is that most companies aren't unique. There are always more "me too" companies than there are remarkable ones. And, unfortunately, if you're not a market leader or the first in your particular niche/space—you're a "me too" company.
So how does a "me too" company create great marketing? They have two choices. They can shift their strategy, focus on a corner of the market and become dominant in that space by identifying an aspect of the product that other companies are ignoring (AKA -- they can become remarkable, find a unique position, or identify a blue ocean). This is the Volvo method. When others car companies focused on fast/comfortable/fun. They focused on safe, and grew because of it.
The other option is to take advantage of new/emerging media and become dominant in that medium while the bigger competitors are slow to adopt. It's not a market opportunity, it's a media opportunity. This is the burma shave method. Burma Shave recognized in the 1920's that cars were playing a much bigger role in people's lives, and they took advantage of this new roadside medium with a campaign that placed a series of rhyming signs along all the major highways. Obviously, the same thing is happening today in all corners of the web (facebook/twitter etc). Those that are the first to take advantage of the opportunities win. Companies that leverage the web have huge a advantage over their competitors.
The secret to great marketing isn't really a secret. So, whether you decide to become a purple cow, own a unique position, or sail to a non-competitive blue ocean—all you're really doing is finding a marketing opportunity and taking advantage of it.