Automatic layout
Assign child layers to a parent with Properties → Layout relationships → Parent, then enable Auto layout on the parent.
Smart layout (modifiers)
Open Window → Smart layout.
Preserved design resizing
Convert a rectangle or ellipse with Edit as path, then enable Preserve design in its Path properties.
Cropping
Select any visual layer, including rectangles, shaders, patterns, text, and images, then choose Properties → Crop → Crop or right-click it and choose Crop.