This is a very big topic, and it takes this whole forum to discuss it. There is no simple answer such as "do these 3 steps and you will have good results."
One of the most important things any new website needs is links from other websites - and these should be sites with good trust and authority in Google. Just learning how to get links from other websites is the focus of another forum here - see Link Development [webmasterworld.com] for lots of help.
Here in the Google SEO Forum, there is an Hot Topics and FAQ area [webmasterworld.com], which is always pinned to the top of this forum's index page. In there you will find two sections, "Some Basics" and "Some Guidelines" that can get you started
Check out each of the forums in the Marketing World [webmasterworld.com] area of this site. Each of them has a forum library link near the top of the page... you'll find a good general gist of how people have been getting their site promoted over the past few years.