Most manga bodies are slim and long, and rather light in build, unless of course they are chibi. In that case you will find that the size of the head is almost as large as the body.
There are also other styles (like in DragonBallZ) where the characters have heavier bodies.
This male body is long and lean. You can see his muscles clearly... he's definitely a fighter! (Maybe a ninja or samurai do you think?)
Start by sketching the guidelines with 30% black pencil. An oval for the head, and larger oval over that for the hair.
Draw simple sticks for the arms with circles to mark the shoulder and elbow joints. Box in the hands.
Add two more slightly curving guidelines in a cross to show which direction the chest is pointing. Two more muscle lines make a V shape on the stomach.
Now fill in the details with an opaque black pencil and erase the guidelines with white. Colour the body in with a skin coloured midtone - pale orange. Add more details with the airbrush using a slightly darker tone with reduced opacity.
For that extra punch use a still darker colour with less opacity to airbrush in more detailed shadows.