Hi, I am a new member to this forum and just want answer to this question.
On Page SEO & Off Page SEO both are merely important for ranking a website well in Search Engines.
On Page SEO deals with the optimization of web page on the page itself so as Search Engine loves it. There are many things that favor On Page SEO. Such things may include :- Fresh Content, Title Tag, Meta Description, Meta Tags, ALT Tags, H1 Tag, H2 Tag. On Page SEO helps your website a lot to kick your competitors from the keyword you are trying to rank for. On Page SEO is quite easier to start with for most of the people. On Page is so powerful that if done in the best way it can rank your website in top position, if your targeted keyword has mild competition.
Off Page SEO deals with the optimization of the web page by process called link building. One important thing to remember is that it's not the quantity matter, it's the quality of back links matter pointing your website for your targeted keyword. Of Page SEO can be done in many ways such as using social bookmarks, article submission, press release etc,. Search Engines don't like spammy back links so never ever create it. Try to do as much as manual work for creating back links, avoid using tools. If you have problem or not much knowledge of it, try it with your local SEO services team.
Thanks and Regards
Richard Smith