Creating Illustrator sea wave designs ? The mesh tool effect can be added to any path such as an rectangle. You can then re-color each point with different blues and white. Create a long rectangle. Select the mesh tool in the toolbar. Click somewhere along the top of the rectangle. Set the color to a light blue and then drag the point upwards. Go to another point along the top of the rectangle and click and drag downwards to create a basic wave and then set the color of the point to a slightly different blue. Repeat somewhere else but upwards (perhaps varying the height) and repeat a couple of times to create a wavy top full of light blues
Create the first design. You can add all kinds of variations to the design such as changing the colors of the gradient meshes, perhaps darker blues. You can also squeeze or stretch or rotate the design as well as warp it using the warp tools included in the application. It is a single mesh at this point. A good thing to do is perhaps save it to the CC library (it can always then be re-used at a later point). You can add as many waves as you wish (by adding as many points along the top of the rectangle)
It would be a very depressing image if there was only one path. Drag the wave to the 'horizon' (wherever you want that on the art board) and re-size the vertical as required by using the selection tool and the bottom edge. Alt / option and create another wave. Re-size that wave by re-sizing the bottom. Also stretch horizontally as well as shift and move it downwards (towards the 'coast' or camera) then alt / option and repeat the same action of stretching the vertical to control the height of the wave and stretch to control the frequency of the wave as well as just select the mesh points and drag up or down to create a different design.
You can also then select the entire selection or individual 'mesh waves' and re-color them using color adjustments via the edit menu as well as recolor using presets from libraries. You can also re-color them by using the mesh tool and selecting the individual nodes and re-coloring them via the color panel. You can also then select the individual waves and re-stretch them. You can also select all the objects and hold the alt / option key to duplicate them to create a more complex designs.
You can also use the color guide panel to create a more unusual and surreal design by changing the color from blues to reds and greens or purples and pinks etc (perhaps useful for hillsides instead)
You can use clipping masks and limit the range of the design. Add a rectangle on top of all the designs. Select all and then go to the object menu and clipping masks