Apart from a thorough understanding of the industry you are in, you need excellent math skills and computer skills. Problem solving skills, attention to detail, excellent presentation skills, etc are essential qualities. You will also need good levels of business sense, excellent communication skills, and good teamwork skills. You must have an organised approach to work and you must be able to meet deadlines. You also must keep up to date with the general scene, by following the developments through newspapers or internet. A thorough understanding of material, equipment & labour costs; regulations, professional standards, etc are also essential traits.