I agree with all of the above suggestions but especially with Apexwork and Shalwan. Research is Uber important, without it you'll be fumbling in the dark. There are loads of free tools for starting a research project, Google Trends is a good place to start and Keyword Planner - try focusing on long tail keywords they are easier to rank for if you're after organic traffic. You should find a niche where you can add value which you give your customers for free, this also shows that you are an authority in your niche. Try not to place yourself in the market only based on price, this will reduce your margins. IMHO research is the key to finding the right products to sell online, whether information products or physical. Good Luck!
If your website is on Opencart, than use "One-page Super Checkout Plugin". It will help to increase the sale of your products.
for e-commerce, i think it is quite important for you to sell something unique and uncommon, in my country, unique things has also become best product such as selling ice-cream online,yakiniku food, shabu" food online. since those unique things will also help you in enriching your page on search engine
Picking good inventory is always a good idea, of course...but don't forget, your store is going to need its own identity if you really want to find success selling online. The most popular online retailers (Vat9, KarmaLoop, ThinkGeek, Zapps, others) don't just have great inventory...they have a great identity to go along with it. They know their niche and they stick to it, which makes it a lot easier for customers to identify with the store and understand how it will fit into their lives. I know that's a little bit artsy, but it's true! Hope that helps. _ Sean
My rank: 1. Smartphones, tablets. 2.Shoes 3.Clothes 4.Other electronic gadgets. 5.Softwares and mobile apps.
Now a days the internet has gotten so vast that you can sell anything. I agree with what everyone is saying, but we all know that people are even selling their services on e commerce websites. We shouldn't be limited to what we sell on the internet. You can sell anything Take and example from Ebay and see what they are doing. Ebay and Amazon are the largest E commerce sites in the world, i think it is only fair that a person can look at their websites and take example from them and look for loopholes and then make something better.