With over 1000 new apps flooding the AppStore everyday, getting visibility can be really really hard. One common strategy, which is still heavily used in traditional Internet Marketing, is to niche it down. Target a smaller audience and strive to be the big fish in a smaller pond by selecting a less competitive marketplace.
You can do this by thinking carefully about which primary and secondary category you want to use when you list your new product.
I like to use 148Apps.biz to review category trends before uploading any new apps. The following chart shows some of the most popular and crowded categories today.