Risk assessment. If you're working in a bathroom and there are razor blades everywhere take steps to remove the danger, if your going to replace a cylinder look at the route you'll be walking politely ask the customer to move anything cluttering your path, also assess the weight and make an arrangement for someone to assist you in lifting it out should you deem it necessary, (never the customer! Never!)
Select the right dust sheets for the surface ie laminate flooring.
Rcd! Every time you plug anything in.
If you'll be working on anything that uses electrics isolate, confirm safe isolation then test the device you used to confirm isolation on a known source. And don't forget to volt pen anything you might touch prior to doing the above.
Safe storage and disposal of waste, and if you suspect asbestos, stop immediately contact your line manager and arrange for sampling. Don't forget those pesky floor tiles they catch people out all the time.
Van. They love an organised van and an organised tool box no use opening the back doors and it all falling out on you.
Ell electrical equipment you carry should be pat tested annually
Data protection. Nothing with a customers name address or job number should be left on display. So if you note something cover it up or store it away don't leave it on the dashboard no matter how irrelevant you think that info is.
Gloves different types for different tasks.
Ladders. Unless it is fixed and blocking you're route never use a customers loft ladder always use the one provided.
Tool boxes should be made highly visible with chevron style stickers to aid the visually impaired. Never leave it in the middle of the room and always try to make the customer aware of its location should they enter the area, same for trailing leads.
If you lift a floor board either place a barrier across the room or place it back before you walk away. An old girl fell through her ceiling a few years back.
Good about the fire extinguisher but they'd rather you weren't a hero and instead got everyone out safely and quickly alerting the brigade ASAP. In areas such as lofts and confined spaces compression is preferred to hot works unless it's unavoidable like gas work for example.
That's all I can think of off the top of my head.
