WordPress has been dominating all the CMS for creating websites in 2015. In ecommerce sector it's not any different. Since WooCommerce plugin is in the game, having fully functional online store is a matter of few hours.
1. Start in very beginning!
Right after you start with choosing of your template you have to keep in mind that it has to be compatible with woocommerce plugin. Best way is to go and pick up from specialized ecommerce wordpress themes collection where you can be sure you'll find the best stuff. Templates vary in different parameters and I highly recommend to check live demos and think about your store and features you'll need in it.
2. Products
After you install woocommerce plugin you'll get section products on your dashboard. For products you can set up different categories, tags, variations, attributes and shipping classes. You can run stock system as well and with good SEO plugin you can optimize your products separately.
TIP: You might find that shipping or weight settings doesn't match your requirements. Remember, there are plenty of FREE or premium plugins which can handle most of eshop related extensions, such as, weight based shipping for WooCommerce Plugin etc.
3. Woocommerce Settings
Before you start selling you need to jump on woocommerce settings and went through all the options to make sure everything is working properly. You need to set up shipping info, emails, payments, tax information, checkout, etc.
You can also follow reports and set up coupons or different types of discounts.
4. SSL Certificate
Last but very important is SSL certificate. It'll secure all your payments and login information of your customers. There are plenty of unsecured websites which get attacked on daily basis. You can find more information about SSL here.
Check video with Best Ecommerce WordPress Themes