Lots of potential in that tank, I can visualize it when it's fully planted.
Like Double J said, more plants

These are 'leaf frogs', not 'tree frogs' so they need lots of leaves to hide under/hang onto. A plant I find that works well for Red-eyes is Pothos. It can easily fill the tank in short order. The frogs love it, and it doesn't need special care.
I don't think you could give them more leaves than they can stand, they'd just be happier frogs.