If I'm using the All-in-One Plugin for Wordpress. Is there anything else that I'm missing for better Search Engine Results?
You need to build great back links and use the target keywords as the anchor text for each link. Also use use keywords as much as possible ion the content without over doing it or making it look like stuffing. I also think there is now a better plug in by the name of Platinum SEO Pack Review. It has upgraded the old All-in-One and added a few great features.
it is important that you use choose carefully the blogs where you comment. Look mostly for dofollow blogs with pagerank to make the back link valuable. I wrote a post on my blog that will sure help you with this.