To your first point, that's the mistake I made as well. The trick (as I discovered later) is, when you first release your app, to put the release date well in advance (say a month). When the app is approved, you can then change the release date to "tomorrow" and it will then show up at the top of the "New Releases" when the time comes.
You can apparently also do this after the app has been released, but I haven't tried it.
Regarding your second point - yes, it is very hard for small entries to be noticed. My app,
Virtual Cricket, competes with the apps of big names such as ESPN, BSkyB, English Cricket Board etc. I believe (very objectively, of course) that my app (cricket scores, commentary, news etc) is better than all of them, but I don't have the resources of a big website to throw behind the marketing nor the brand that catches users' attention.
But you just need to persevere, try to market the app in as many ways as you can with the limited resources that you have and hope that users will notice the quality of your work and that the cream will rise to the top (eventually).