Follow the editing tips at the top right of the page when you are editing your hubs. My formula, which has lead to me never having had a hub unfeatured due to quality is:
Write at least 1,500 words
Spell check and grammar check it thoroughly using words
Add at least 10 pictures (I use my own, but you can use correctly accredited photos from the internet as long as that is allowed)
I add at least one pod such as a poll, map etc depending on the hub
I use Google Adwords to carefully choose my title
With this approach, I now have 115 hubs on HubPages.