From this tutorial learn to create a sun background effect in Illustrator.
Using the Polygon tool draw a polygon.
Select the Pen tool and draw a triangle.
Fill the triangle with a soft colour which contrasts with the black background. Make more triangles. Rotate them.
Keep doing it until you get an image similar to this.
Make few more triangles and be sure that they all touch in the middle. Now you will get a cool sun effect.