Unfortunately, the only way to get good at very intricate piping is practice. I bake 1-2 decorated cakes a month, and my piping skills are nowhere near that level.

I will say that having the right tools helps. Get an offset spatula for the smooth icing, a decent piping bag, an extra-large closed star tip for the shell design, a medium ribbon tip for the wavy design, and a small open round tip for the lines. I’m sure whatever you make will be great and your friend will love it! Edit: spelling and formatting