Dragging between sheets can be difficult with the mouse unless you use the Alt key. If you have a workbook maximized, e.g. only one sheet is visible, you can drag a selection to another sheet by holding the Alt key while dragging and pointing to the sheet tab you want to go to. If you hold Ctrl and Alt you will copy instead of move. You can also press the Alt while dragging with the right mouse button. Pressing Alt is also useful if you have two windows visible side by side and are copying between them.