Try to establish a left-to-right, top-to-bottom reading flow.
Arranging elements this way ensures the flow of information feels
natural for the user, because it follows what they are used to from
text. For right-to-left languages it can (or should even) be right to
left, top to bottom.
If the exact coordinates of items in an editor matter, the editor
should draw a grid background (or a grid floor in a 3D editor). For
example the UV Editor or Graph Editor. This grid can go in one
direction only if there is only one variable axis. For example the
Dopesheet displays grid lines along the horizontal axis to represent
frames, but the vertical axis represents different animation channels,
which keyframes can't be moved between.
If the exact coordinates of items in an editor with scrolling on two
axes does not matter, the editor should draw a dotted grid. For
example the Node Editor. The grid only serves as a reference point for
view transforms, so you can see the view scroll even if there is no
content.