Place the blades precisely and very quietly in the water.
The left hand should be nearer the stern than the right by about a hand's breadth, to help the overlap and avoid scratching your knuckles later in the stroke.
Early and Mid Parts of the Stroke
Start pushing with the legs (the blades must be covered), keeping the back leaning forward and shoulders forward and relaxed. Do not hammer the beginning, just place and press.
Listen to the noise of the sliding seat as you push. You should hear a continuous smooth sound that lasts for most of the stroke.
If the slide gives a quick brief noise then you are jabbing too hard with the legs and the back is giving way: the force of the leg push should be smooth and continuous.
During the stroke push with your legs progressively almost hard enough to lift you off your seat (least hard at the beginning, most at the end) as you hang on the handles with straight arms and with shoulders still relaxed and extended forwards. This is called "Hanging On The Oars", and it helps to coordinate the leg and back muscles, while applying good power.
There is something about top sculling that is mysterious and unexplained.
Perhaps the something is "Touch", a refined ability to sense and control the force on the water through the stroke.