Look at pictures of knights and the type of armor they wear. Study the lines and textures of the pieces in order to accurately replicate them.
Sketch the rough outline of a male manga character. Draw his face with a strong nose and slightly narrowed eyes, creating a mature look.
Place a helmet on top of the knight's head, using smooth, rounded strokes to denote metal. You will not need to add hair to the knight because it will not show through his helmet.
Broaden the knight's shoulders with almond or triangle-shaped epaulets or shoulder guards.
Add a chest plate on which you can put a crest or other insignia.
Draw the leg pieces of armor, with joints where the knees bend. Add boots for his feet.
Practice drawing hands in different poses, such as holding a sword or knife.
Produce variations of your knight character based on what actions he is performing. Draw him leaning forward as if dueling an opponent or ducking to avoid a blow.
Research the type of weapon your knight is likely to use. Common choices are swords, daggers, bows and arrows and staffs of different lengths.
Draw the weapon you have chosen as if it is lying on a table, and you are looking down on it. This will help you get the basic shape down. Later you can draw it from varying points of view.
Make a basic sword by drawing a shape similar to a pencil. Put a line down the center of this shape to render it three-dimensional. Create a handle by adding a plus-sign (+) shape at the bottom of the sword.
Use action lines to show that the knight is swinging the sword. Draw slightly curved lines from the sword outward.