Observe your roof. Monitor your roof throughout the snow storm to determine if ice and snow really need to be removed. Flat roofs are especially prone to snow buildup damage because there isn't a way for the snow to drain or fall from the roof. If you've had renovations and walls have been removed, look for sagging in your ceiling and cracks in plaster.
Access your roof. If you need to get onto your roof, look for a cutout between the attic and the roof that will allow you to easily climb on top. Otherwise, you'll need a ladder. Climbing up on your roof from a ladder is easily the most dangerous part of this task. Seriously consider whether you are qualified to do this. If you fall, the medical bills could easily exceed the cost of repairing your roof. Consider calling a professional.
Shovel snow with care. Shovel the snow off your roof, but be careful to not even touch the rubber membrane with your snow shovel. The smallest tear can cause a terrible and hard-to-find leak.
Locate your gutters. One of the most important factors in removing snow and ice is to allow melted snow to exit the roof. The alternative is that melted snow will refreeze, block the gutters and undo all of your hard work. Clear the gutters of any ice or snow with hot water.
Clear paths for drainage. Pour hot water on the roof to clear paths for drainage to the gutters. Place electric heating coils designed for de-icing in this path to keep the channel open, or lay down chemical de-icer in the path.
Remove the remaining snow. Spread a chemical de-icer over remaining snow, or melt it with hot water to allow it to drain. If you are using electric heating coils, they can likely survive wet conditions. Regardless, unplug them while you are spreading hot water on the roof to prevent creating an electrical hazard. After you have removed or melted the ice from the roof, spread another layer of chemical de-icer to prevent new snow buildup. Ensure that drains are clear and that there is ample de-icer near the drains. (It's water soluble, so the more you melt, the more you will use.)