How to get a glow/lightning trail effect

There are various Shader types in unity in Default, and you can use the "Unlit" Shaders for that problem. No matter the ambient light, the color will remain the same, Bright or Dark.

I've never tried using a 'glowing' effect on a trail, but you will need a whole Particle System for that. Try following Mirza's tutorial: https://www.youtube.com/watch?v=rJFxS2W7nrE

After making a 'glowing' Particle System, just minimize its range to zero, and then attach it as a child GameObject to your main 'object'.

As your object moves, the particle system also will follow your object, and it will work fine.

If is it a straight-line trail that you want, a simple trail renderer with an Unlit Shader will do.

But for a straight-lined glowing trail, you'll need a special kind of shader for that.

Or, you can just diminish the Particle System's particles' size into a dot, and let the system emit tons of them, making it 'look' like a line.

But since it will eat up a tremendous amount of processor resources, the second option is not recommended.