How do I know when I’m using the right number of keywords on a page?
 

How do I know when I’m using the right number of keywords on a page?

It's not important if you target 1 keyword or 10, but a competitor who targets only one word on a page will always beat a page which targets multiple words. Ranking in search engines is a competition. Start with targeting one word, and when you have achieved top rankings for your primary keyword, then try to get multiple keywords.

I don't think it is still matter that how much keywords are on your web page.