Before you create your domain you should have already decided the niche. You can find some great niches and keywords by going to google.com/trends. It shows the most popular latest searches within the hour and you can even see the graph for how well that keyword is doing for the year.
About the plug-ins I'm not exactly sure. Feel free to check my autoblog packages and see if there's one that suits you. Have a great day.
silicuda is right.
u need to make ur permalinks, search engine friendly, so ur pages get indexed.
Also, update ur categories with keywords for better search rankings
than customise ur permalink structure with /%category%/%postname%
this will put ur niche kw in ur links
the best thing is to look at the customer first and do research WHAT the customer wants and WHAT is in demand...and THEN create the blog.
I, however, often look first at the avaialable resources available to sell...eg. i look on Clickbank for products and THEN decide to make a blog where i can sell those products.
Because you dont want to run into the problem to make a blog about
"incdentarial delaphantitis in infants and smaller children"...just to find out you dont have any related product or affiliate programs to monetize that niche