You should be going for a milky look to your paint.
Marbled wood effect paint.
To water down your paint a bit add equal parts water to your acrylic paint and mix with a wooden skewer.
Then mix your paint in disposable cups.
First you will need to marble the wood panel.
How to paint a marble effect faux finish.
How to draw marble.
Use a dry blending brush to smooth out the fine veins.
Sponging white back into the marble pattern is a secret weapon.
If desired sponge on lighter shades of green to soften the tabletop and add more depth to the surface.
Repeat this step at least two times and add in some white veins to create highlighted areas.
Dip a detail brush in diluted white or very light green paint and add fine lines to simulate veins.
Blend out fine veins.
If you add too much water and you will lose the vibrant colors.
This technique is messy so i use scrap cardboard to cover my table.
Choose your colors based on the type of marble you wish to recreate.
Create the look of marble at a fraction of the cost with a faux finishing technique.
Slowly drip the paint into your liquid starch mixture.
For this i have an acrylic paint pouring technique that will give you a marbled look.
Start with your plain wood panel and protect your work surface well.
When you re satisfied allow the paint to dry for several hours.