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DO be aware of the feelings of staff. If they are not used to using an application, they may not initially use it on site while there is a lot of machinery around as it is safer for them to use a pad of paper and then the IT in the office.
DO make sure that you keep in touch with users during the early phases to address any needs and make sure the system is being used the way it was intended. If it is not, find out why and address it. It may have nothing to do with the technology.
DON'T keep changing systems. Hardware and platforms are being updated fast. Find one that works and stick to it for a while instead of changing all the time to updated versions unless they offer real business worth or are updated under contract.