Google 'offset smoker mods' there's a wealth of info out there on how to improve the offset smoker. things like raising the fire grate so the ash doesn't choke your coals and lots more.
Cheers tommo , I've seen a few mods , like bringing the chimney down to coocking level , and the heat baffle , I think I'll have a cack at those first , it's there anything else worth looking at