What fleabay's answer describes is modern technology: rendering with shaders computing a detailed 3D shape from affordable amounts of data (a relatively simple base mesh and normal or displacement textures) and modeling with comfortable sculpting tool and extensive automatic processing.
What you seem to be doing, on the other hand, is very old school modeling, with carefully designed triangles, at the uncomfortable detail level that is too complex to be easy to edit but still too coarse to look really good (see the hands, the armpits and the crotch of your figure).
It's hard to tell, without knowing your rendering technology and the intended look of your finished assets and scenes (what kind of game is it?), whether you should embrace modern technology as fleabay suggests (probably the easier route) or adopt a more stylized, “retro” look with a much lower number of triangles (requiring more skill but probably less work than what you have now).
Suggested references for low poly humans and creatures: Quake, Unreal, Virtua Fighter, Darius Gaiden. Are you aiming for a more realistic style?
