Honestly, I don't have very specific advice. I do know writing about interesting topics, and making sure they are well written will get you higher hubscores. Christian hubs get rated lower than my other ones, the ones that get scored the highest are ones that have a more general interest rather than very specific like about writing or cameras. By adding more details such as pictures, videos, rss feeds, news, always seems to help my hubs. Sometimes if I notice a hub is beginning to fall, I will look at it and see if it is missing one of these features and then add it. I usually will see an instant increase shortly after. I also find that my longer hubs do better than my hubs that are around 500 words. Although I don't write for length, I write that amount that will sufficiently cover the topic I am writing about.