Sunbursts Tutorial Author - Slick Illustrator (http://www.slicktutorials.com/illustrator-tutorials)

When it comes to impact and relative simplicity, it is very hard to beat a skilfully composed sunburst. Used most effectively by manga artists, they are surprisingly eye-catching, and can make objects & characters stand out perfectly.

Step 1:   Create a new document - it doesn't matter what size, because you can resize vector graphics to any size you want without losing quality. Then double click on the Polygon Tool icon and enter the settings shown:

This should leave you with an equilateral triangle:

Step 2:  Go to Object > Transform > Scale and enter the following settings (this should stretch your triangle vertically):

NB.   At this point you should consider selecting View > Snap to Point from the main menu - This step is not mandatory, but it does make things easier.

Step 3:  Select the Rotation Tool and click at the top point of the triangle. Since you chose Snap to Point it will line up perfectly. This is the anchor from which the triangle will now rotate around when you use the Rotation Tool.  To finish this step, give your triangle a color fill with no stroke.

Step 4:  While holding down SHIFT+ALT on the keyboard (SHIFT+OPT for the mac), click a little below the bottom of your triangle and drag over to the area shown below.  Holding ALT down will make a copy of your triangle, and since you are also holding SHIFT the triangle will rotate in increments of 45 degrees (1/8 of a circle). You should now have 2 triangles as shown:

Step 5:  Use the CTRL+D shortcut to duplicate your last action. Press CTRL+D 6 times in total to make 6 more copies of the triangle, each rotated 45 degrees, and complete the sunburst look.

Now use the Selection Tool (black filled arrow) to drag a selection rectangle around all of the triangles. Go to Object > Group to put all of the triangles together as one group. Use the Selection Tool again to click your sunburst group, then grab one of the corner handles that appears, hold SHIFT+ALT, and drag it outward to expand the sunburst. In this step, I also added a black background.

Step 6:  With the sunburst group selected, open up the Symbol window (Window > Symbol) and click the New Symbol icon.

Step 7:  Click the button in the top right corner of the Symbol Window and go to Save Symbol Library. Give your new library a name, and now your symbol will be accessible in any future document.

Variations:  Repeat all of these steps with alternate settings to make sunbursts with different looks. This one uses a scale setting of Horizontal: 100%, Vertical: 600% and a rotation angle of 20 degrees. To get an angle of 20 degrees, I brought up the Info Window (Window > Info) and instead of holding SHIFT while rotating the 1st triangle, I looked at the Info window and rotated it approximately 20 degrees. Make sure you use a multiple of 360 for the rotation angle (i.e. 20, 30, 45, etc.):

The final result: