You should start off by taking a paintbrush and dipping it inside the blue paint. It depends which shade of blue you are planning to pick. You can either pick the deep blue which will highlight that you are painting an ocean, and if you pick a light blue shade, it will highlight day time and will add a little bit of a refreshing ambiance.
After you are done with dipping your paintbrush in whatever type of blue shade, it is time for you to run the brush on the top of a bar of soap. It will help you add a little bit of slimy affect which is required by you in order to give a realistic picture to the ocean waves that you are planning to paint.
Now use the paper and paint on it using wavy patterns. The soap will help you create the type of effect that is needed to show waves. Keep repeating this process until and unless you see a lot of blue wavy patterns on the paper.
Now there will be areas on the paper where you will show that the waves are adding a bit of white foam. On those areas, randomly place newspapers.
Now use ocean colour over the newspaper with different colours including blue and green. Use different colours and let them blend into each other. Now wait and let it dry.
Now it is time for you to remove the newspaper. With the newspaper totally off, it is time for you to use a sponge dipped in a bit of liquid mask. Use the sponge on areas where you think the waves are going to crest.
In order to create a flow-down effect, keep painting all over the paper and keep blending different colours into each other. Also add dark blue paint in order to add outline and foam. It can also be used to add shadows to the image. Once you are done drying the painting, remove the liquid mask.