Hi D Arun,
I'm by no means an experienced or seasoned hubber but, having just arrived, I've got plenty of tips and advice fresh in mind from a whole variety of hubs, learning centre articles, and external sources.
Make sure you tick all the boxes. Literally. As you write, keep looking at the top right where it checks little boxes based on each goal you reach. The number of words you have is a huge one, 3 or more pictures go a long way, and even if it really isn't needed, add a rating capsule, video, or poll.
I've only written one article at the moment. It's featured with a rating of 72: not fantastic, but certainly a solid point to build upon. I simply checked each of the boxes. I added a star-rating capsule which wasn't necessary and no one has used, but it assisted in getting it right up there. I also included a video against my initial judgement, and I believe it benefited the article's content in the end too. These restrictions can certainly enhance your creative process, another benefit aside from a rating-enhancer.
I don't know if or how the content of your articles affect your rating, but many people say content is king (good Hubpages advice as well as career). My hub received a few comments and three-figure views, which leads me to believe a hub's rating is at least partially weighted by the amount if interest people have in it. If this is the case, I recommend (on behalf of those who've recommended the same to me) doing some keyword research and advertising your hubs. Writing them is only a fraction of the work, spreading the word via social media is definitely the next step.
If you've done all of this or it isn't the advice you're looking for, I'm happy to revisit my answer to assist you.