The first couple of roses you pipe will be difficult because of the mechanics and you will probably expect them to look perfect. But they are pretty simple once you learn the technique and it really translate to most flowers, this is only my third time making them. 

I will say is that most of the times one single rose won't look good on its own, the magic happens once you put a bunch of them together. Even the wonkiest flower suddenly becomes pretty, nature doesn't make perfect and you don't have to either.

After that is avoiding keeping the piping bag in your hand for long period of times because buttercream melts very fast and it becomes sludge and you can't pipe with that.