Use a free tool like wordtracker or Google keyword tool. Look for low competition, high search volume keywords
Google Adwords, Word Tracker and Keyword Country are good tools for keyword research, analyze and choose.
The Best free tool to select keywords for your website is Google Adword Keyword tool. For a page take not more than 5-6 keyword, Also make a good mixture of High, Medium and Low Keywords. Best to choose those keywords that have low competition and high monthly searches.
Google Adwords Research Tool Although this tool is primarily meant for Adwords bidders, this is also widely used by webmasters and publishers to measure the popularity of different keywords based on their Google search volume.
Google Adwords is a best keyword tool. While choosing keyword consider following points:- Business Type Local or national or international Targeted Country OR City Targeted Product or Services etc.
This can bring confusion to someone new. Low competition, in Google keyword tool, actually mean that the competition is low for Adwords (not for ranking in Google's SERP), the advertiser won't have much competition and will have to pay less for PPC. If you are looking for keywords from other side, as an Adsense publisher, you will actually benefit if the competition is HIGH, because it mean larger PPC and more money for you as a publisher.
One of the best adsense niches to get into is the coupon niche, just make sure you do your research and find the low competition one. A great rule of thumb is making use of the free keyword competition analyze tool by traffic travis, make sure you find 2 sites in the top 10 that have both pr 0 and 0 backlinks to the specific page. Also make sure that they are not going for the keyword in the title or description. (traffic travis makes this easy by showing an X when the site does not have the keyword in these specific places. So go ahead and type coupons in the Google keyword tool and see the amazing keywords you can dive into. Hope the helps and gives you a head start!
To choose best keywords for creating content for your website you can use the free Google keyword tool or other tools for finding keywords like Marketsamurai, wordtracker, or you can brainstorm some and then you will use the keyword tools to see if they have any traffic. Look for keywords that have low competition(you can check them by hand too, go to Google, write the keyword in quotes and if they have less than 30.000 competing sites, than you have good chances to rank on the first page with little work, my suggestion is to search for keywords that have even less than 30.000 competitors, maybe 10.000 or 5000, this way your articles will be on the first page in no time). And another tip: use keywords that have a high buyer intent. In other words you want to use keywords that will bring you a lot of leads, sales...etc not useless traffic.
To choose the best keywords, first choose those keywords or keywords phrase which are relevant to your website. You can use Google adwords which will help you to find out the best keywords. Choose those keywords which have low competition with high search volumes.