I want to know how to chose the best keywords to get heavy traffic? Keyword shouldn't have any competition, like nil '-' which is shown in adwords tool ?
For any Adsense, it will be better to choose good and high volume search keywords. That will help for generating revenue because it's impression will be high and naturally search and click volume will be high
Google keyword Tool is good one - https://adwords.google.com/select/KeywordToolExternal you must try it.
Use the keyword tool and select product name keywords. They work well for me and gives me laser targeted ads with very good CPC.
For Adsense keywords selection, keywords two aspects hold importance: keyword's popularity is important to know how if the keyword is searched often or rarely. Keywords pricing holds importance as how much people are paying for specific terms. Getting keyword popularity is harder than keyword pricing.
chose the keywords that has a decent level of competition for your site. If you target them correctly you could get a very good google ranking especially if you do some seo for the website. Getiing a good rankings will drive Organic traffic to your site and this type of traffic is the most valuable one and i`s also highly targeted.
I always target a big keyword for my main domain but smaller keyword for each articles that easier to get rank on top of Google. Build from small and you'll be top in no time.
I've also found it extremely helpful to use Google Insights for Search, it will help you find out how people are really searching and you can see the keywords popularity over time, check it out at http://www.google.com/insights/search/ Good luck!
Choose the best keywords by choosing a bunch of words that relate to your site... for example if my site is about games, then my keywords will be: games xbox 360 ps3 playstation gaming system online multiplayer shooting... etc. I hope I helped!