The best tool for keyword is Google Adwords. You should find out the most profitable keyword for the site.
I think not only Good keyword but also Good HTML, Good tags, Good content and lots of submission in local search engines websites.
Yes of course .Its act like blood in an site. Keywords are necessary at all places. Keywords should be placed in such a way that all other really like it as it is.
key word research is a basic as well as very important in the SEO filed... You need to see Exact search volume with the help of Exact match type box..Moreover, you need to check the competition in the double quote ("Key word")
Yes, keywords research is very important. You can do it using google adwards keywords suggestion too. Do keywords research on the bases of your business country.
Do your keyword research prior to deciding on a promotion, and before building a site. Find keywords that you can compete with, or you will not get acceptable page rank in the SERPs, which means no free search traffic.
keyword is the most important for developing and seo any site. use google adwords tools for keywords research.