Tap one of the arrow keys on your keyboard to lock movement along an axis while moving an object. Left is the green axis, right is the red axis, and up is the blue axis. This is one of the ten SketchUp tips that every modeller should know that I highlighted in my post 10 SketchUp tips every modeller should know. You can also lock an axis reference by holding SHIFT.
The Move tool can be used on more than just surfaces and edges. You can hover over individual points and click to move them in any directions if you enter the Move tool without choosing anything.
Change the position of an object:
Place the pointer over the object until it changes to the Move pointer mode. If you're moving a text box, make sure the mouse pointer is over the text box's boundary.
Move the thing to its new location by dragging it. Hold down SHIFT while dragging the object to have it move in a straight line.
Select the object you want to rotate with the Select tool (Spacebar). Press (Q) on your keyboard to activate the Rotate tool. Hold down the mouse button and drag outwards, perpendicular to the plane you'd like to rotate on, from the point where you'd like to rotate from.
Select the entities you want to move with the Select tool (). A dot displays next to the current layer of the selected content in the Layers panel. Choose Move to Current Layer from the menu that appears when you right-click your selection.