You need to write more hubs with good quality content. Hubs with quality content has higher chances of approval.
I see you are from Indonesia. Asian country publishers have difficulty in getting adsense approval - sometimes they have to wait for longer period (about six months) as Google monitors their site before giving approval.
But Google is not very strict on this - As long as the site as good original content, they do give approval. Increase your hub count and then apply again.
Also making money through Hubpages is not easy - there is a huge amount of hardwork and gestation period - understand that by reading FAQ's and other hubs. Ensure that it is inline with your expectations.