If your question is,How many keywords for the good quality and optimize my site

Only recommended keyword is 5 to 10? but its up to you,

 but the best match of matching keywords to search engine,i recommend

5 to 10 keywords thats the best match when people search  and  find

 your own site.And for the set up of your keywords  you need  some

highly and recommended  competitive keyword  you may visit to adwords.

And also look out for one or two long tail keywords,(these are the phrases

 that people might search for when they are  looking to a site where the same of  yours

then you should make sure the your site is optimized around the keyword,

THESE ARE THE SAMPLE TRICKS OF KEYWORD:

1. At least one keyword should be in your site’s title.
2. At least one other keyword should be in your site’s description
3. Ideally your domain name will also have one of your keywords in it
4. And you also want to ensure that the main pages on your website containaround 2-5% of your keywords – this is known as keyword density.

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