In my time on hub pages I have deleted one hub. It had no overall effect on hubpages score or article score. The best way to increase hub article score is finding readers. The best way to increase hubpages score is be part of the hub pages community. Asking questions which receive answers is going to help with the hub pages score.
The best overall way to increase both scores is find a niche, write more than one hub to the niche, then put your hubs out to social networks. These hopefully to niche interested readers. Their comments and shares will help your ranking on search engines.
Low competition highly searched keywords is what you want. Write naturally making sure your keywords are in the hub no more than three times. It is more important is have them in a well written summary.
Do we know what we are talking about? We have over 200 articles of our own published. Have been writing content for websites, our own, and for others, for over a year. This includes writing niche specific articles for others. Some member of the corporation has been publishing on seven writing platforms including enzines and our own blog some for over a year. Hub pages is still our favorite.