Many ready-made paint colours are available at art and paint stores, but if you prefer the challenge of mixing your own colours, you can create a neon green paint colour at home with just basic blue and a very bright yellow paints. When mixing colours, keep in mind that neon green is located on the yellow end of the green spectrum on a colour wheel.
Dab a little bit of any basic blue paint on a palette with your brush. Write down approximately how much blue you put on the palette and keep track of all additions to this colour so that you can replicate the colour later if desired.
Add a very bright yellow to the blue and mix the two colours together with the same brush.
Keep adding more bright yellow until you get the ideal hue of neon green. If you add too much yellow, you can add a little blue paint, but do so sparingly.
When choosing a blue paint, be sure to pick one in the centre of the blue spectrum instead of a blue that has too much green or purple in it.
If you keep mixing colours but cannot get them right, start over instead of trying to fix it.