Before we start our aquascaping, we need to consider placing our focal point at the area where it will draw the viewer's attention. The focal point is the 1st thing to grab the view's attention before he or she look at other things in the aquarium. The aquascpaing focal point might be a rock, wood or even a plant. The focal point placement could follow the "golden ratio" or the "Nine square rule".
The main focal point for "Sunnygrassland" is the largest Okho rock (main stone) located on 1/3 of the aquarium. As the length of my aquarium is 45cm, 1/3 of the aquarium is about 15cm.
I have sub-divide my aquarium into 3 segments in the horizontal and vertical axis forming a total of 9 boxes. One can place their focal object on any of the 4 intersection points which I indicated in blue circles. In my case, I have placed my main stone on 1 of the stated location.
More details can be found in the following links:
1) Golden ratio
2) Nine square rule