Best strategies if you want to get into ecommerce online retail store?

Here are some strategies if you want to get into ecommerce online retail store. Which do you prefer? Any other strategies that are effective for you?
1) Online retail estore
Sign up as affiliate/ associate/reseller of big sites like Amazon, ebay and then setup a website adding in the affiliate links and then promote/market the site

2) Dropshipping
Find a unique niche you are passionate about (like flip flop shoes or animal hairs ), outsource to suppliers/dropshippers, setup site and promote/market the site

3) Warehouse
Same as 2) but instead outsourcing to other suppliers/dropshippers, you DIY or keep inventory and provide delivery to your customers.

4) Social Media marketing
Sign up as affiliate/ associate/reseller of big sites like Amazon, ebay and promote/market your affiliate links on social media like facebook, twitter

5) PPC marketing
Sign up as affiliate/ associate/reseller of big sites like Amazon, ebay and promote/market your affiliate links by paying for traffic at PPC like Google Adsense

6) Bricks and mortar retail store (Reverse webstore)
Sign up as affiliate/ associate/reseller of big sites like Amazon, ebay and promote/market the products offline by setting up bricks and mortar store selling those affiliate products