Launch as fast as possible and start building links at once.
It is better to target the less popular keywords - it is impossible to compete against Wikipedia when you are new:
"For the amount of effort it would take you to rank #12 for the head term of your choice, which will result in marginal traffic even if the head is huge, you could rank in the top three for a huge basket of tail terms. Additionally, one of the things you’ll notice is that conversion rates for head terms are terrible. People searching for the terms on the head are either just beginning their research into a topic or are less sophisticated. Generally, those are not the searchers you want. Longer, specific queries are more common among people who have done the research and are nearing a purchasing decision."Publish data of some kind you can´t get anywhere else:
"Pretty soon you’ll be cited as an authority on the subject — because, ahem, someone who publishes repeated analyses of raw data is an authority on the subject (or at least appears to be, which is 90% of what matters on the Internet, for better or worse)."Source: Kalzumeus