Near Top Lane
Wall Warding - Blue Side Top River Entrance
As shown in the diagram below, the highlighted area with a bright line is where you need to ward. This method is recommended when you cannot cross the river due to heavy enemy presence on the lane.
After placing the ward, the visibility should be like this (able to see enemy champions in the brush).
First, locate the thick bush near the wall (similar to a crab claw plant?). Stand on top of this plant (position your character's legs to block the bush), then find the triangle shape marked on the inner side of the wall. The right angle of the triangle extends towards the right with a yin-yang boundary line. Ward near the position indicated by the orange arrow, ensuring an 80% success rate.
Be cautious not to place the ward too low, as it might go into the curved area under the wall. Placing it too high might reveal the river brush. This position can be tricky to find and requires practice.