Firstly, let’s create a gradient background fill as shown below

Draw a vector curved line

Select splatter stroke from properties window. Increase or decrease the diameter of stroke based on your requirement.


Now provide some inner glow and outer glow effect.


Final effect

I decided to write tutorial on this effect while working on www.theretirementbubble.com
Tags: bulb effect, bubble effect, Fireworks stroke effects, oil splatter stroke