Ventilation and things

Just wondering how you guys have built ventilation systems. Im in a closet, a decent sized one. Id like to just cut a hole in the wall, but how do I pull that ventillation through? Go through to where also, out up the roof would be best but that would probably be quite difficult unless I spliced this ventillation into an already existing outlet... this might not make any sence.... anyways any tips on this type of stuff would be great

through a charcoal bucket back into the room if possible