All great planted tanks start with the right substrate. In a high tech tank one generally injects C02 and add nutrients to through root tabs or liquid fertilizers. In a low tech tank one uses dirt as a sources of nutrients for plant growth. I am a fan of low tech as it reduces the added work of daily or weekly doing of ferts. In my tank I choose to go with Miracle Grow Organic Choice Potting Mix (MGOCPM) as the nutrient rich base layer capped Instant Aquaria and Eco-Complete.
In order to hide the dirt start by making a border of your capping material around the front and side of the tank. This will create an ascetic border and hide the layer of dirt. I generally do an 1.5″ ish layer of MGOCPM. In a planted tank you want to shoot for at-least 3″ of total substrate thickness to make it nice and easy to get plants rooted. If your substrate is to shallow you will ricks plants being uprooted and floating around your tank.
Finally you will want to cap your base layer find a top layer of Eco-complete or your substrate of choice to make an appealing base layer.