The must fun i have is when doing particle system. The above particle system has a material with the additive shader. The texture is a circle with shiny edges created in photoshop. The size over lifetime property is set to small-big curve. Use color over lifetime for different colors. And there is no starting speed, its set to burst so a sudden force gets applied to it.
I am not a professional yet :D. But what i do to create particle system is make a image in my mind of what i am going to do before i start it. I look up to other references, their colors, speed etc. Make simple textures in photoshop that i need and start to make it. Tweek some settings, increase-decrease , bend , twist to see what fits. Then if it fits the game, i just simply save it :)