If it isn't a popular site but say has really good authority like a .edu or .mil or .gov sites commonly do, they rank well have great authority but arn't indexed very often because of this. At least this is my opinion they arn't crawled often with exception of course. You should try using a pinger service to help it get indexed , hmmm its what I do. muh ha ha.... http://pingoat.com/ works well for such evil tasks of getting a not so popular page indexed fast.
pay him It comes around whenever it feels like. So, theres not much you can do except backlinks and content, so when it does come to you, you have a lot instore for the bot.