Not too much detail to go from here; however what matters the most is do you like it? If you don't you'll constantly mess with the scape and stress the fish, or even worse, grow disinterested. You'll want to consider an aquascape that will support the life you want to have. Want fish that like to hide? You must make caves! You want low par LPS + SPS? Ensure you include overhangs to shield low light corals. Also do research on building the scape itself. There are lots of tricks such as using acrylic rods to achieve new shapes by combining smaller rocks you cut and shape. Youtube is also your friend if you're the visual type for your research.
Step 1) Read this for the basics along with a ton of great examples -
http://reef2reef.com/threads/tips-and-tricks-on-creating-amazing-aquascapes.97209/
Step 2) Do more research and start picking out inspirations. Remember, you can break rock to create scapes you see in large tanks in small tanks -
http://reef2reef.com/threads/show-off-your-large-tank-aquascape.59909/ and
http://reef2reef.com/threads/show-your-nano-aquarium-here.5098/
Step 3) Use cardboard to make the footprint of your tank
step 4) When you're happy with your scape, go through your requirements checklist and ensure everything is there (x amount of negative space, overhands, fish caves, coral real estate, space for coral to GROW)
Step 5) All good? Leave things where they are, sleep on it. Stare at it longer, imagine the flow of water, do you see massive blockers, is there multiple paths for the water (careful about putting scape on the back wall and leave space from the glass for cleaning it).
Step 6) Cement/putty the rocks together so you don't have avalanches due to shifting sand from residents
Step 7) Put in tank and finish the rest of the process.
Here's my process/scape. While I like the scape, I made two big mistakes that I will resolve in the next build. I forgot little fish caves for gobies, blennies and the other small filler fish I like and I didn't build enough tall real estate for the SPS I want. I ran out of space for fish and corals due to this.
The first scape. I really liked the way it looked, but the pieces were too large for my 420 liter tank and it caused major water flow issues.
So then I started planning the second scape (this is a real pain to change btw). I used cardboard with the dimensions drawn on it and the bed as a height reference.
Here's what it looked like in the tank at first.... pretty empty.
And here it is 6 months later growing in. Not the best shot, but you get the idea that you need to leave space and the scape drastically changes as coral growth happens.
