Download Textures for sea and surf - Texture Zip
First A Couple of General Notes
When you are using any of the paint tools you must set your presets prior to choosing your color or it will revert back to the default color
also once you choose your color the preset will go back to showing none but it does in fact keep your choice

Remember to Save often, once you save - clear your undo history.
If you find a setting you like or think you will use often refer to this snapshot tutorial by Debbie Hardisty on how to save your favorite brushes.
Saving Brush Settings to your Easy Palette

Also most all the settings specified in this tut are done with the brush panel.So once you set your Preset.....all other settings can be done from the brush panel
If you are not familiar with the brush panel settings and where they are located I would recommend referring to this tut prior to starting

This can be done with a Wacom tablet or with a mouse.The settings are all approximate as each person will use a different amount of pressure or a firmer or softer stroke.Also remember the undo is a very important tool and you will need lots of patience. A lot of steps seem repetitive but when you are trying to achieve a certain look you may have to try several different tools to get the look you want.So it is kind of a back and forth process.(which is where the patience comes in)

Painting in Mode versus not

Please note that you may find it much easier to manipulate your painting if you were to paint in object mode.
Advantages to painting in mode is that you can paint a little bit at a time making it an object. If you decide later on down the line that you don't like that particular tree in that spot but it might look better on the other side of the canvas, you can simply move it over.
It also makes it easier should you require to blend certain aspects of your painting.

All colors listed in this tutorial are using the Ulead color picker using the HEX #
This was painted on a 600 x 400 canvas to help with the detail and then reduced to 85%

Click on Mode
For the sea.
blue-gray shade,
Color hex:#A0B0B8
Airbrush size 5 soft edge 50 transparency 50
For surf
light-blue shade
Colo .hex:#80A7C4
Airbrush size 30 softedge 100
transparency 50

For surf and sea
blue shade
Color hex:#758E9D
Airbrush size 5
soft edge 50 transparency 50

For the Rocks
Dark Brown
Airbrush size 10
softedge 35 transparency 10
Color hex#2A250B
Med Brown
Airbrush size 10
softedge 35 transparency 10
Color hex#654E2C
Light Brown
Airbrush size 10
softedge 35 transparency 10
Color hex#AEA699

Using the smudge tool to blend your paint......Go in one direction only and try to follow the contour of your picture or as Acadie puts it let your strokes flow with nature

Smudge Tool
Shape ...round
Size... 20

For background sea
Airbrush size 20 softedge 50
transparency 37
Color #7A99AD until happy and once over
all surf but top spray area

Oil paint light stroke size 22 transparency 93
Color #EFF2F5
multicolorsliders 0 4 13
over spray running in direction of your surf

For Surf
increase transparency to 96 over other white area

multicolor sliders 0 33 22
darken and fill keeping uneven color

Warp tool size 20 level50
softedge 50
run gently over waves and
running in an upward motion the direction of the spray start to peak your spray
Paint Water Drop - preset none
size 10 softedge 100 brush over rocks to blend but be certain to
leave variances in color

Working on the Surf-Spray
Chalk size 12 transparency 92
multicolor sliders 0 11 7
curling motions upward and in direction of spray
oil paint drop size 15 transparency 75
multicolor sliders 0 7 4
random 30 brushhead size 2 density 21
oil paint thick size 15 transparency 76
Color #E8EDF0
multicolor sliders 2 8 13
random 11 brushhead size 6 density 17

Paint brush ribbon preset size 100 transparency 50 softedge 50 Color#507189
Texture calmsurf (or your own)
drag from top to bottom on a right to left angle lightly repeating until you have a natural look of sea

Warp size 30 level 40 softedge 50 very gently run across the sea moving very very slightly
in a wave pattern

Bristle smear Preset coarse
size 45 level 40
quick soft clicks over breaking spray in an upward motion moving in the direction of the spray then run from right to left over the surf to the left of rocks creating a backwash effect
Dodge tool size 1 level35 softedge 50 make small highlights in your sea.......trying to place them above the dark spots in the sea

Dodge tool size15 levrl 10 transparency 26 following the contour of the breaking surf highlight the white areas

Burn tool size 1 level 15 softedge 50 accentuate dark areas in sea next to white areas

Burn tool size 15 level 12softedge 50 accentuate dark areas in breaking surf ,
Burn tool same as above rub over the rocks and once over the sea lightly