The best way to promote products online is to sell your products through your own brand in all aspects of the World Wide Web. Design a website, this is your base or "hub" make sure it is fully complete with everything you can tell and show about your products until you can't think of any more. On this website don't just showcase your products everywhere, tell your audience a little about yourself and build that trust...Trusted leads become return buyers

You then want to Mix it up with social media, create a full range of social media pages, Facebook, TwitterInstagram ( this one will be ideal to show case any pictures you have of your products) and on these pages link back to your site so that all are connected together. 

Now as well as doing all the above you want to build yourself an E-Mail list using your website and social media by having a form your potential buyers fill in on your website, this will add their email to your Autoresponder which brings me to the next source to add to the mix. 

Aweber or  Get Response ( join Get Response with me and you get £20) are the two main autoresponders out there and I highly recommend either. Within your autoresponder sequence you can then start adding messages you want to send to your list on any day or time you wish and it will automatically send them out. In the messages you want to have all the links mentioned above as well as special offers on your products which link back to your site. 

So you should hopefully see here my method i call Collect-mix-connect, It forms a Circle of what eventually turns to profit for your business. The answer to the question is all aspects are the best way but only if they are mixed and connected well together.

To your success