For the page itself, you need cover art, an informative description and a couple of screenshots. The game can be an early/development version, nobody minds as long as you're honest about it. Of course, the more polished it is, even at an early stage, the better an impression it will make. At a minimum, I would add a title screen, especially if it's a realtime game, but that's just me.
As for choosing a name, it's a good idea to do it early, because changing it later will break links from elsewhere to your game page, but also because having a name will make it easier to talk about it (and also to think about it). But choosing good names is tricky.