I am doing keyword research and new in this staff so how to ensure i am doing right keyword selection?
Keyword research is very important. It is often the difference in a website failing or succeeding. You need to find keywords that produce enough relevant traffic. You also need to choose keywords that you can realistically get good rankings for. Use a keyword tool such as Google's keyword tool or wordtracker. Make a list of any good potential keywords and their search volume. If you need help thinking of keywords consult a thesaurus or your competitor's websites. Once you have a fairly complete list you should analyze the competition for the keywords that provide the best potential traffic (based on volume & relevancy). Do some searches to see who is ranking for those keywords. Make note of where those websites use those keywords on their websites...page title, meta tags, headers, etc. Also check how many links those websites have. It helps a lot to use the SEO for firefox plugin. It shows a lot of helpful stats right in google searches. Eventually you will find some keywords with decent volume and lower competition. Sometimes it is a good idea to target a mix of keywords with varying levels of competition. Mostly base your keyword choice on what you will make you the most money but is still attainable traffic. If your seo skills are strong you can confidently target tougher keywords. If you are new to seo, it helps to target keywords with lower competition, but those usually have lower search volume. If you target enough low volume keywords it can add up to a large amount of traffic.
Ideally you should find keywords that will convert in sales, that have a decent search volume and a relatively low competition. These tools will help you: http://tools.seobook.com/keyword-tools/seobook/ https://adwords.google.com/select/KeywordToolExternal http://freekeywords.wordtracker.com/
While you searching with your keywords, if your competitor site would comes that keyword is right choice.