I have 2 youtube channels and combined I have more than 100M views, my 2nd Channel is growing by 70% month to month and I estimate that this channel by itself will produce 30-50M views per month end of 2016. With that said the single most important stat you should be on the lookout is engagement rate. Try to have videos that have a high engagement rate, preferably anything that is above 50%, if you want further details and other techniques happy to have a call