JS_Harris - 10:52 pm on Mar 25, 2010 (gmt 0)
Welcome to WebmasterWorld anrf,
What should i do next for better rankings
Create unique and useful original content on something you are knowledgeable in.
How many additional domains i can have to leech their ranking
As many as you want but the leech effect will dry up quickly, if it doesn't get you banned from search first.
Therefore, can i optimize things until i get at top10-20 or i need to wait before i make any further page title\kw\text updates (for how long)?
Top 10-20 will drive little traffic, top 1-5 are the only positions guaranteed to be above the fold on page 1. You can optimize pages to some degree but optimizing pages alone can only improve rankings so much. You'll need a solid internal link structure as well as incoming links from trustworthy places. When you make changes wait a couple of weeks to see if anything changes in Google, a couple of months in Bing and six+ months in Yahoo!
re: #4, the benefit to owning your domain name in .com/.org/.net etc is in brand recognition and so that nobody can copy your site and outrank you with your own domain name. If you own the .com version it's less of a problem, if you own just the .net for example I'd grab the others and make an offer for the .com.