How can I?

Hello everyone...
I am beginner in SEO field and don't know much about SEO. As I read SEO is divided in two part On page and Off page.
I understand about Off page but in case of On page I am nothing. That's why I am asking for help to understand about On-page SEO for a web site.
In my mind I have few questions
1. What are the thing now we have to look in a website for SEO friendly?
2. How can I judge that this website need On-page SEO?
3. Where I can learn about SEO for a site?
If anyone has one blog, link, post that can help me to learn On-page SEO please share. I am not in condition to go for any type of course or pay to learn SEO please help.
Thanks
Dwivid

http://seomoz.org is a nice site to learn, you will have to learn every day because google is always changing the rules

try seo moz for on page optimisation

Too late with my answer

On site seo presents your site to search engines in an easy to read way.. You will learn all you need here on bhw. The White hat forums has stickys....what is your site build on ? If it's wordpress use yoast or all in one seo plugins...there are YouTube videos showing you how to set these up

I can help you with some tips about on-page SEO that I got from an ebook. You can add me on skype if need be.

just google seo blogs then you will find a lot of blogs on seo from them you can learn alot.
thanks

mate on-page SEO is usually easy since your making changes within the website and those may here header tags,your title etc.