A landscape that works does two jobs at once: it has depth — it feels like you could walk back into it — and it has a focal point — one place the eye naturally settles. Both come from how you arrange things, not from how well you draw them.
Stack It in Three Layers
Painters split a landscape into three depth zones. The foreground is the stuff nearest you, along the bottom of the picture — big, detailed, often a bit shadowy. The middle ground sits behind that, where most of the "story" usually happens. The background is the far distance up near the horizon — small, pale, simple. Put something interesting in each of the three and the scene gains real depth, because the eye reads near, middle and far the way it does in life. Cram everything into one band and the picture flattens like a stage backdrop.
Notice the size cue while you're at it: the same object drawn larger and lower reads as close, and smaller and higher reads as far away. In the toy, drag a tree down to the foreground and it grows; push it up toward the horizon and it shrinks. You're not resizing it by hand — its depth is doing it for you, exactly like perspective did with the box last term.
Give the Eye Somewhere to Land
Depth alone isn't enough. A picture also needs a focal point — the one thing it's actually about. Without it, the eye wanders and gives up. The focal point is usually a single clear element (a lone tree, a hut, a figure) placed where the composition leads you, often off-centre rather than smack in the middle. Drop the dashed focal-point marker onto one of your elements in the toy and the feedback turns green: now the picture has a centre of interest, and everything else becomes supporting cast.
Spread It Out
One last move: don't bunch everything into a corner. If all your elements pile into one side, half the picture is dead space and the other half is a traffic jam. Spread them across the frame — some left, some right, some near, some far — so the eye has a path to travel. The toy nudges you on this too: bunch the shapes up and it tells you they're too crowded; spread them and it relaxes.