Which site do you want to promote? If you want to promote a YouTube video, it is easy to stay high in a new niche. I hope you should look for some SEO course to learn, this is the way that pro make their site on Goole top.
There are many techniques to SEO your key word, but there is one main point: You have to get as many traffics as you can. It will help you rank higher higher in Google.
Ok, this is a easy to understand definition which I have found on Internet: "In search engine optimization (SEO) terminology it is the term used to describe the value of a Web site, where the measurement is based on the quantity of quality Inbound links (also called backlinks) to your pages...