I am making my first "real" cake for my daughter's birthday this weekend. Thanks to these forums and youtube videos, I have learned A LOT! . I did a partial practice run a couple weeks ago.

I'm planning to frost the cake with regular white icing (powdered sugar, shortning, etc.) and then stick fondant cut-outs to it. Any tricks to sticking the fondant cut-outs to this type of icing, and can I do it the night before?

I had considered covering the entire cake with fondant, but since I'm stacking 12" and 8", I decided that rolling fondant out to cover a 12" cake is going to be a little difficult for a newbie like myself. So to save myself some stress, I'm going to use regular icing, and smooth it as best I can, thanks to help from videos!

Any tips are welcome!! Most important question is about decorating the night before.

Of course you can decorate the night before. That is actually better on you for the stress factor. That way if things take longer than you thought or you run into a mishap, you still have the next morning to work on it.

To glue fondant to buttercream, I use either vanilla or piping gel. You just need a little bit of either.

is it ok for the cake to be uncovered overnight? I don't have anything large enough to cover it.

Un covered as in iced but sitting out in the air? Yes. The icing keeps the air from drying out the cake so that it stays moist.

If you mean un-iced, I'd just wrap it in plastic wrap.