I've noticed that a lot of newbie decorators are overestimating their abilities in a not-so-good way.
It's one thing to be confident and try new things, but it's another to go online and post questions about "how do I make this cake" with photos of carved tiers covered in fondant and gilded royal icing scrollwork. I've seen a lot of extremely complicated photos being used to demonstrate what the final cake needs to look like alongside a request for tips on "what pans do I need to buy to make this cake."
The problem with this isn't that people are trying to do something new, it's that they're trying to do something new but they've already promised someone, usually a bride, that they can do it for their wedding cake. This is a surefire way to end up on the cakewrecks "what the bride ordered/what she got" page. This won't only affect the beginning decorator, it's going to affect someone's wedding reception, and not in a positive way.
I'm going to suggest something that a lot of people (probably the ones who go online to ask how many cake pans they need to make a wedding cake) won't like. If you are an experienced decorator, and you see someone asking questions that guarantee that they're trying to reach waaaay outside their ability level, tell them to stop. You can be nice about it, but be honest.
Tell them that the cake they're trying to imitate is probably more ambitious than they realize. Tell them that if they're asking if anyone has a recipe for a wedding cake they shouldn't be selling cakes yet. Tell them that they shouldn't be experimenting on someone's wedding cake. Tell them that if they have to ask how to make a gumpaste rose, they shouldn't be trying to do a Sylvia Weinstock design. Just tell them.
Don't worry about being called mean, or being called a bully (the most overused term of the year, IMO), because that's what's going to happen anytime you tell someone what they don't want to hear. It's one thing to encourage someone, but when I see people respond to this kind of question with "Oh, you're going to do fine!" I shudder for the bride's sake. I know they're not going to do fine, you know they're not going to do fine, and isn't it better to tell them that they should probably scale their plans back a little?
There's nothing wrong with having the first wedding cake that you make be a simple design. There's nothing wrong with learning to bake before you start selling baked goods. There's nothing wrong with learning new skills before you need them. There is something wrong with using a paid cake as your learning curve.
If you can't look at a picture of a cake and see exactly what you need to do to make it, don't promise anyone that you can. Investigate it first, then let them know yes or no about whether you can pull it off. And if another decorator tells you that you should practice before promising, don't call them a bully, tell them thank you for giving you a reality check. Then start practicing.
Kara Buntin owns A Cake To Remember LLC, online cake supplies at www.acaketoremember.com and www.acaketoremember.etsy.com