I used a bottle warmer in the beginning, but now I am lazy and use the microwave - just be sure to invert the bottle at least 10 times to get rid of hot spots... also, older micros are much worse for hot spots than newer ones
In Canada, you should use freshly boiled water if you are making formula from powder. The water needs to be at least 70 C to kill the bacteria in the powder. Nestle does not recommend premaking any formula with powder - it should be done as needed.
To make your life much easier - get some concentrate! It's actually cheaper than powder in the long run and SO MUCH EASIER! It can be premade up to 48 hours ahead of use. And you don't have to use boiled water since it is sterile. I have always made it in a small juice jug that seals (I have one made by Starfrit with the silicone seals). I keep the whole jug in the fridge and pour a bottle when I need it.
If you really want to cheat - keep just the concentrate in the bottle in the fridge and use hot tap water to get a warm bottle
Super fast for the middle of the night