I am suddenly posting like a maniac. Sorry, but I'm trying to gather a bunch of info! I was watching this video here:

http://www.wilton.com/decorating/icing/using-decorating-tip-789.cfm#video

And, I have some questions. Aren't you supposed to scrape off your spatula after each swipe? It seemed like she had a lot of icing building up on her spatula.

Also, I thought you started on the sides, so that you created a 'lip' of frosting around the top, and then you 'came in like an airplane' to make smooth edges????

Yeah, that's not the best video I've ever seen on icing a cake. I recommend Sharon Zambito's DVD for a better technique.

Plus, I think that big spatula is much harder to use than a good metal bench scraper. If you're learning how to ice cakes, get Sharon's video and a bench scraper. Both are money well spent. You'll have much better success than the technique shown in this video. Get one like this:

http://www.cheftools.com/Fat-Daddios-Stainless-Steel-Dough-Cutter-Bench-Knife/productinfo/02-1894/

Do NOT get one with a handle that sticks out on either end because you won't be able to get it flat on the cake board.

That's one of the worst videos I've ever seen on icing a cake. Edna has a good video on youtube

There are a million different opinions on the right way to ice a cake. I think this video is supposed to be more of an idea on how to use the large tip 789 to get your icing on the cake. It is one way to get a bunch of icing on without crumbs in it, then smooth out after all of the icing is on the cake. She doesn't wipe her spatula after each swipe at first because she is just trying to spread around all of that icing. When she starts to smooth the icing, she does start to wipe the spatula. She didn't get the cake perfectly smooth, but I figure that was in the interest of time - show you the way so you get the general idea...
I also prefer a bench scraper to get my sides smooth - much easier to get the sides a consistant thickness. However, Wilton does not yet sell one like that... I use a plastic wallpaper smoothing tool from the paint/wallpaper section of my favorite local hardware store.

I think that is one of the worst videos on how to ice a cake that I've ever seen. She's got bumps and lumps and makes no sense when she talks about the "front" of the cake???...then says "center" at one point??? Glad she wasn't MY Wilton instructor!

You'll find that a lot of people do it differently.

I start by plopping a lot of BC on the top with a straight spatula, spread it out towards the sides while letting the extra hang over the edge, add more BC to the sides, then smooth the top with 2 or 3 spins of the turntable--an extra spin or two (with the spatula at a 45 degree angle) to knock down the extra BC towards the sides (wipe the knife once onto the bowl or bucket to remove the extra BC that's been scraped off before it hits the floor), then smooth the sides with 2 or 3 spins of the turntable depending on the diameter of the cake. You'll need a really good turntable that doesn't wobble to do it fast.

Find out what works best for you and stick with it!

I agree, it's not the best instructional video I've ever seen. You would think Wilton would have done a better job producing such a video.
Yes, I did see several things I would have to disagree with, but I'm not in a nit picky mood this evening.

All Hail Queen Edna! Queen of Cake Decorating Videos!
Plus I think she has really good hair!