1) Cut a semi circle of radius 10cms.
2) 5 Cms from the top, mark the centre and make a crease at every 30 degree interval.
3) Once you made the crease, start folding along the crease line in alternative as shown.
4) Apply some glue inwards and stick.
5) Finally stick a small star on the top.
6) Your blah blah blah tree decoration is ready!