Icing a cake now, need help QUICK!!!

I started icing my cake, everything was going well but I didn't have enough icing around the corners and at the bottom so I kept adding and kept trying to smooth.

Afterwhile it seemed like my icing was "lifting" off my cake in small chunks. Why isn't it sticking to the cake when I try to smooth?

Do I need to wait for it to crust before I smooth? How can I ensure that I have enough icing around the corners? When try to smooth the corners I can see cake through the icing.

There is a article on here that shows how to ice corners. Sometimes my icing tries to lift to. It seems to me that maybe my icing is just a little to thick. But, I just carefully slide my knife off the icing where it's lifting and then I can usually go back over it and fix it. I've been letting my crust 20 min or so before smoothing. I was using the hot water method but I just started doing the viva paper towel method and it's great. So, easy!

What is the cake supposed to look like when you before you smooth?

Does smoothing help take the ridges/waves out from going over it with the spatula? I think I did just fair on icing my cake because it looks like the icing has little holes in it and the waves from the spatula doesn't help either.

With the hot water method I got it as smooth as I could before I let it crust then I smoothed it with the hot water and spatula, but, with the viva I just pretty much make sure there aren't any major lumps, bumps or bruises in the icing and let it crust. The smoothing method takes out all the little lines from the spatula's. Actually, I was quite shocked the first time I did it. I was putting on an fbct so I wasn't really being that careful about lines since it was just getting covered up. I was just trying it out for practice so I could do on my next cake. I left some pretty major lines in it and it came out so smooth. I don't mean to keep going on. I just love this method. I'm sure yours is great. Most of the time we are the only ones that looks that close.