!!UPDATE: HATENA HAVE FIXED THIS GLITCH!!
Cloning stars can be easy for some people and hard for others.
There is a few ways to clone coloured stars.
It is a glitch that Hatena will probably fix! =(
You need at least 1 green, 1 red, 1 blue or 1 purple.
Add the coloured star to a flipnote. Now click the total stars about 10 times.
Now erase the stars, click back and keep doing that until you get back to the flipnote details screen. Sometimes it dosen’t work.
Add the star at the flipnote details page. Now click the total stars. Erase it and click Back. Keep repeating that about 5 times. Sometimes it dosen’t work.
I hope it works for you!