This year my theme inspiration is snow, white, peaceful, candlelight, "All is calm, All is bright". 
So I started researching how to add snow to my tree.  I owe a debt of gratitude to bloggers I found that tried different methods and discovered if you buy a spray snow can in the store, it will end up looking like spray paint.  My research led me to SnoFlock, which I bought on Amazon - it looks like this and you can
 buy it here.  I bought the 2 lb. bag and that was perfect (my tree is about 5-6 feet tall and pretty full).
For this Project You'll Need:
a tree (as far as I know, it works on real or artificial)
SnoFlock
a spray bottle full of water
the instructions tell you to use a sifter, but I'll explain below that it's not necessary
a face mask
a throwaway glove (optional)
Something about it seems scary or overwhelming, but it's not - you can do it!  I started with a live tree.  Everything says to do it outside.  Luckily it was nice enough on Black Friday that I was able to do that.  I put the tree in its stand and put it on my patio.  I started with a small amount on a test branch.
 I loved how it looked but it felt like it would take forever.
I also wasn't sure how well the 2 lb bag would cover the tree, so I tried to use it conservatively at the beginning.
I was in a race with the sunset (and dinner plans) so I got braver and early on I quit using the sifter - that really would have taken forever.  I used one hand to pull a handful of snow dust out of the bag and then had the spray bottle in the other hand.  You have to spray the branches before dropping the snow on; then spray the powder as you're dropping it; then spray the top of it.  All this adheres the powder to the tree.  When I got braver, I started grabbing big handfuls out of the bag.  Using your hand really adds precision, you can add snow or build up snow exactly where you want it.
I was loving it - it was turning out exactly how I wanted.  I felt like I was in a snowy Colorado ski lodge!
I thought it was very realistic looking!
I pulled it in through the sliding glass doors and getting it settled some powder fell out but not too much.  I think from start to finish it took me about 2 hours.  
Then I added lights and candle lights and was so happy with it, I considered not even adding decorations.
But I ended up loving the decorations once they were on!  The big white puff balls you see I found in the Target Dollar Spot (for $5 per set) and they were play snowballs for kids.  I used a needle and strung them on fishing line to create a garland.
I'm very happy with it - it's snowy and magical!