1) Product Picking
You should first start choosing a macro topic - you can find it on Amazon:
http://www.amazon.com/gp/site-directory/ref=nav_shopall_btn
You should choose a product category that people would buy online, this means that the socks are unlikely to be purchased online.
For this go for razor or a blender products kind.
2) Keyword Research
Now you've product category and you need to find all ways people is searching on Google for this products.
My advice is to use competition analysis on SemRush and you need to do this things:
- Find competitors in your topic
- Scan them to obtain all keywords they're ranking for
- Download all keywords and sort them by competition (from easy to hard)
3) Start Writing Contents
Now you need to build your contents based on keywords with low competition - here brief
guide on how I build contents
4) Off-Page Seo
To make your website authoritative on Google's eyes you need to send regular and quality backlinks.
This means that you need guest posts, web 2.0 properties, comment links and citations (with or without link).
This are only advices based on my experience and I think you can do awesome projects with this advices.