Get registered in social bookmarking sites like digg, reddit, mixx... and then submit your story there.

Always give interesting title to your story that will help you to get more visitors. You can also use targetted keywords in the title it helps to give good SERP ranking

If you are changing the design of the site like color or templates then I don't think it affects in ranking.

But if you are changing the h1 tag, title etc then there is affect in ranking. if you are choosing relevant and proper tagetted keywords, good title then you can find your ranking goes up

Future of seo is very bright because i think SEO gives results that helps to people to find desired results or resources so it is always going on

Social bookmarking and adding your link on already index page are the best ways to get index fast.
You can also make xml sitemap for your site and submit it to a google webmaster