I like to group all the plants of one certain type together, rather than space them throughout. There are many, many ways to landscape a "horizon" in your tank....I found comments on
http://showcase.aquatic-gardeners.org/2006.cgi the tanks very interesting. The comments from the judges are at the very bottom of the page.
I also don't plant everything in the middle (width-wise) in the tank, I try to stagger back to front to try and create depth. I also try to mix texture. Right now I am almost relying solely on texture actually, because I have no color in the plants except for the foreground wendtii.
I love the reds you have, and your plants are growing really well. Great job!
I have learned sometimes I just have to keep messing around until I like it. I'll have all my plants planted, go to sit back and relax....and get up and replant a plant 2" over....lol....