I am doing a cake for my sister this weekend. Its a three tier cake with BC icing and fondant accents. I wanted to use luster dust on the accents but I am a little unsure how to do this.

Do I just brush it on dry? Do I apply it once I put all the accents on the cake or do I do it before? I believe I read somewhere on CC that you mix luster dust with a liquid/booze and 'paint' it on. Any feedback would be awesome!

You can do either depending on the "look" you want. Brushing it on dry will achieve a more subtle, shimmery look and mixing with alcohol will give you a more flashy, metallic effect.

I don't think there's any hard and fast rules about when to apply the luster dust. Can you handle the accent pieces to put them on the cake without smudging the luster dust? Can you manage to paint them if they're already on the cake without getting the luster on the surrounding surfaces? I guess it depends more on what you think would be easier.

You can do it ANY of the ways you stated. I have found if I use everclear or vodka and paint it that way I use less luster dust. If you dry dust it on it uses more. It is easier to paint them off the cake, let them dry, and then add them on if they are more intricate pieces, that way you don't get the dust all over the other parts of the cake - though people do it both ways. If I have simple pieces sometimes I paint them once they are on the cake so I don't have to try to pick them up with the dust on them. You should do a couple of experiments so you can see whether you like the look of wet painting or dry dusting the luster on, and how easy/difficult it would be for you to do it on or off the cake. I LOVE luster dust!!! It is so pretty!

Good luck!

how much dust to how much booze? Am I making a paste or is it just a little dab will do ya?

When I am painting I don't have set ratio or anything. I make it thinner than a paste, though. If I want it really dark/heavy I use more dust but if I just want a more subtle effect I thin it down more.

i also read somewhere that you can spray luster dust on, is this true? and if it is, how would you do that?

I am a great fan of luster dust. It's practiically on all my cakes!

If you're dusting it on, you should be aware that some of it may land on places you don't want it to. I always dust my ornaments or decorations away form the cake.
If you use alcohol (make sure it's 96%), you can paint it either directly on the cake, or paint the ornaments before sticking them on. Depending on the colour, I usually mix my dust to a oily consistancy. But you really should try it for your self to find out what works.
The spray is great too! But it's very hard to spray evenly, if you don't want your entire cake to be sprayd.

Good luck and have fun!