How can knowing the top keywords help my website optimisation efforts? Do I hide them somewhere in my website even though they have nothing to do with the purpose of my site? U can tell I am a novice in this, so forgive me for asking what the pros might consider such a silly question.
Hi, If you're just starting out then I suggest you read Google's Webmaster Guidelines. (Hidden and irrelevant text is a big no-no.) Also read SEOmoz's beginner's guide. It will help you understand SEO better and covers quite a few topics. Once you have a grounding of the basics, you'll find it easier to move on from there. Good luck.
Use GoogleAdwords to know the necessary keywords. Choose exact words with medium search volume and low level of competitions.
Effective onsite seo will involve including your keyword in the text about 1-5% of the time. It should definitely have to do with your site as they should be what your site is about, along with related keywords.