some steps to promote a new website are:
major task to promote your site on internet is link building and some linkbuilding techniques are given below.
Id start from day 1, when you fisrt build your website. Invest in writing high quality unique and fresh content about your subject, include the keyword in the H1, the page title, and the meta tags, then move on to off page seo
You can promote your website both offline as well as online also. You know little bit in offline method but now I am discussing in online menthod.
Do On Page and Off Page Optimization.
In On Page Optimization focus on Meta Title, Keywords, Description, Alt Tags, Bold Tags, Header Tags where as in Off Page Optimization focus on Blog Commenting, Forum Posting, Bookmarking, Guest Article Posting, Directory Submission...
You should to do Social bookmarking andlocal listing for new site and then after do local business listing according to that site theme. Join group,community related to that site on social media sites. Do article,pdf, classified,image sharing, forums and other activities.