There are many techniques and tools to get consistent scroll designs onto cakes.
My favourite is the tissue paper transfer technique.
Print out free design templates found online.
You will also need tissue papers cut according to the height of your cake,
edible markers and pins.
Trace the design onto tissue with edible marker.
Use a medium tip, not too fine and not too thick
so that the ink would not be too wet for the tissue.
Pin it onto cake.
Use a thicker tip to trace the scrolls.
The ink will seep through.
The maximum times for tissue reuse is three,
after that repeat the transfer of design from paper
or whenever the tissue is not usable anymore.
You will get faint line like this.
I use a Wilton tip 3 to pipe royal icing and make them more swirly at the ends.
Then optional adding of teardrop shapes,
or any small piping if you wish to make the design more compact.
The quickest technique is off course free hand piping,
something I would only be able to do if I start practising everyday for 2 years.
That's only an estimate.