choose keyword with high searches and also refer with keyword planner tool

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You should search those keywords which has high searches and low competition. Even you should go for Google Adwords and get the best keywords out of it so that you can rank your website on the best keywords related to your niche.

Keyword is important as we know,Use Google analytic tool always and keep on eyes which key words getting traffic for your site

You need to do keyword research with research tools , you can get such tools from SEOclerks.

Use Google Adwords -> Keyword Planner. Shows useful keyword ideas relevant to your site!