0 - work out which keywords you want to rank for. Use exact match (for now) for your research.
1 - build a website, which is genuinely good-looking, based in Wordpress. Make sure it has a blog section with a few unique articles published.
2 - install Yoast SEO plugin
3 - make sure you have keyword on the page (title, h1 and main text), but in a natural context, ie don't make title 'widgets, blue widgets, cheap widgets', but rather 'Widgets - an awesome place to buy them'
4 - build social profiles which link to your site: Twitter/Google+/Facebook/
5 - Google SEOmoz beginners' guide, bearing in mind some of their link building tactics are a waste of time, think which will realistically work. Also make sure you find out what the Penguin update is.
6 - experiment with what they say. I did this for about a year, and yes - it did work and I started making good money following their advice, coupled with enormous persistence
7 - come back here, because at this point you'll have a much, much better idea of what you're doing
This is just my advice. If you want to take more risks with buying software, spending money on services, etc, rather than just with your time, start with tactics you see here.