The Company I work for builds stages, installs lighting, audio, video screens etc and we do a couple of fashion show events in the year - Britain's Top Model and other bits and pieces. One of the main things I would recommend is that you check out any contractors you are using very carefully in terms of insurance, competency etc. There can be a lot ofdifferent issues to consider especially as the event organiser. The Purple Guide HSG 195 - event safety guide is all there is really out there in terms of guidance for event management. It's not great but will give you a good "checklist" of things - structures, fire and emergency planning, toilets, noise, electricity, waste management, first aid etc.