Talk:Tutorial: How to Play/@comment-122.151.23.233-20151230232716/@comment-27233821-20151231000047

For increasing the star level, you need a copy of the same card.

Then you go to the strengthtening tab (3rd one from left to right), and choose the green tab. At the left big square, you drop the base girl (the girl that you want to increase), and the right one, you choose the copy.