I think this can be a good thread to get some ideas on how to get started with ecommerce. Some of the questions that goes through my mind are:
1. Go for single product/category or go for all categories.
I think go for a category like apple watch accessories for example.
2. Work as an affiliate for one of the big boys or drop ship?
I think it is better to start as an affiliate to see the potential and than try to drop ship to increase your margins.
3. SEO Traffic strategy-How to create a winning presence on search engines.
Don't really to be honest, need to learn it.
4. Good themes/platforms to use?
I saw this plugin which you can use with wordpress
http://alipartnership.com/aliplugin/
Also heard a lot of good things on
http://www.shopify.com/online
Hi Orisin1 
here are some answer according to my views on the eCommerce vertical.
1. start with a wide range of products to target as much users as possible and start to minimize till you get a better understanding about your user base preferences.
so if you chose to start with Apple watch i will even go on all Apple products and side merchandise like cover cases chargers and more
2. there are a lot of benefits to work as an affiliate and keep working as an affiliate even after you "see the potential" first of all network will likely get a better deal from the direct advertiser than a single person so in sense of margin you can make more as an affiliate than
working direct, you can also get support and help from your AM where in most big eCommerce companies you wont get that help, faster payment terms and other benefits you can have as part of Affiliate network.
Also keeping with your network will show commitment and trust which can get you benefits with other campaigns and will allow you to receive prizes and other perks like we do in affiliaXe - http://affiliaxechallenge.com/
3. As you cant do brand bidding you can create SEO campaigns around specific products or you can build an eCommerce site and do SEO to get more and more traffic to your site.
4.these are nice platform to help you solve a lot of small stuff but not really mandatory, you can get all the tracking links and LP's from the network which will make the plugin not relevant and you can save the money.
regarding
there are a lot).
hope that answer your questions and looking forward to see other comments here and get some ideas on other angles 