Make sure the grid is On (Shortcut: Ctrl + G). Go to the View >> Camera Projection menu and select the Orthogonal command to change the camera view to Orthogonal mode (Shortcut: Ctrl + Q).
Note You may optionally adjust the density of the grid lines via the Preference panel (Shortcut: Ctrl + P).
Press the F or A, S keys to switch the camera to a front or side views of the character. The front view is suitable for adjusting the hands, and the side views are useful for modifying the head, spines and legs.