Start with checking out Josh's Frogs website.
Josh's Frogs How-To Guides » Blog Archive » Terrarium, Vivarium, and Habitat Information They cover everything you need to know about the best way to build your vivarium. I have found this to be the most in depth yet concise and easy to under stand guide. They even have charts of "if you have this size tank ---> use this many bags of substrate, this many bags of drainage layer." They also have another section where you can buy an assortment of plants, based on the size of your tank and what animal will be in with them. So now assuming you have your; drainage layer, substrate barrier, substrate, all in the tank. plant your plants and allow your plants a week or more so they can get a strong rooting before you put any animals in the tank, so the gecko doesn't knock them over.
As far as personal experience, I used and recommend, ABG mix substrate, a Ficus with a thick and strong trunk and branches. I bought and replaced my ficus 3 times because my crestie kept out growing them and I had to put in ever thicker branched ficus trees as I found them. Pothos plants, grow fast, they have strong stems and leaves that will support a full grown gecko, they also will climb up things when they run into them. I do not recommend using leaf litter over the substrate, when you feed live insects they immediately take cover under the leaves and by the time your gecko finds them, anything you dusted them with has already rubbed off. I instead used moss from the woods behind my house, I went through a few different kinds till I found a species of moss that would survive in my tanks. I use 3 different species of Isopods, and 2 species of springtails as my clean up crew(poop and fungus eaters) so I have never had to pick up a single poop and my tank smells as fresh as the day I planted it(a year ago). I recently added red wiggler worms to aerate the soil. I used alot of cork bark tubes for hides, the isopods do not seem to eat the cork bark like they did with other types of wood. When your all done planting your tank, go around and fill in any little cracks in the wood or tight spaces that crickets can get into that your gecko can not, other wise you will be like me and have mass cricket breeding and endless chirping in your tank. Also make sure nothing is touching the screen top to your tank, crickets and other bugs can squeeze through the smallest of holes. USE DISTILLED WATER when spraying your tank down, the calcium buildup that you get from using tap or even bottled drinking water is almost impossible to get off with out using harsh chemicals.
This was my first Vivarium build, notice the tiny ficus in the back right, It looked big compared to a baby crestie, but in 6 months, did not have any substantial growth. Also I built my substrate up to high, right up to the air vents in the front of the Exo-Terra Tank. I kept finding what looked like dust or sand building up in front of the tank, which turned out to be the spring tails that were walking out the air vents like lemmings, walking off the edge of a cliff, one after another.
Can you spot the gecko? This version was revised with some live moss and a taller but still thin ficus.
This is how It looks today. The Pothos and ficus have to be trimmed down once a month so they dont touch the top. I tried alot of different plants that did not survive, so these are the survivors
