Now I have looked for a tutorial but all of those makes the rays thicker at the end not the other way around like I want it. I think this method (https://www.youtube.com/watch?v=HNQqHqtmgZ8) should do the trick but I dont seem to know how to apply it to my needs.
What you need to use is the 'Star Tool' which is bunched in with the Rectangle, Ellipse tools.
Just click and drag and a star will emanate from that point. Whilst still dragging use your up and down keys to increase or decrease the amount of points on the star. Further more you will want to elongate the arms by distancing the outer points from the inner points, you can do this by holding down 'Ctrl' and dragging away from the centre point.
Hope this is clear,