The three primary colours on the colour wheel are red, yellow and blue -- all secondary and tertiary colours come from these three primary hues. When you want to make shades of green, including lime green, you can easily accomplish the task by knowing the correct primary colours to mix.
Pour a measure of yellow paint into a mixing tray or container. The amount of paint you should pour depends on how much lime green paint you need to make. Be sure to remember how much yellow paint you use.
Pour a measure of blue paint into the same mixing tray as the yellow paint. The measurement of blue paint should be equivalent to the amount of yellow paint. For example, if you used 1 cup of yellow paint, you should add 1 cup of blue paint. If you used 3 tbsp of yellow paint, then use 3 tbsp of blue paint.
Use a mixing utensil, such as a wooden stick or spatula, to mix the yellow and blue paints together. Mix the colours together until you have a consistent green colour, with no streaks remaining.
Add more yellow paint to the mixing tray to create your preferred lime green colour. The yellow paint should be added gradually, a few drops at a time. You can always add more if needed, but you cannot take away what has been added. Stir the yellow paint into the mixing tray until you have a consistent lime green colour.
Add a few drops of white paint to the lime green paint if you need to lighten it a little. Add a few drops of black paint to the lime green paint if you need to darken it. Add the paint in gradually, instead of adding a lot at one time. Stir the paint until the colour is consistent, with no streaks remaining.
Use the same brand of paints for best results.