Just give it more time. Once the plants become larger then you can start making design. This is one reason why I like aquascaping so much. The 'picture' doesn't stay the same; it grows and evolves! It's a living art, actually~ Sometimes I don't even have a design at the beginning. I would put something that vaguely resembles what I had in mind. Then, somehow, when the plants have all settled and grown more, I can look at them and make the appropriate design.