Set up your workspace. Lay plastic down on your work surface. Set your canvas down on the table or work surface. Be sure you can pull a seat up to the surface so that you can see your canvas and work comfortably for a few hours. Use a drafting table and prop it up at a 45-degree angle if you want. Use an easel if you own one and pull up a chair. Keep your paints on a side table for easy access. Fill your cup with water. Lay out brushes and paints. Use your palette or the plastic cover from your paints for color mixing.
Draw a horizon line--where the sky meets the water--onto your canvas. Start the line about 4 inches from the side of the canvas and continue until it goes off the page on the opposite side. Add a jagged line in the empty space next to the first line until it meets the horizon line to depict tall grasses. Curve another line diagonally down to where the horizon line meets the jagged grass line. Curve the line a bit until it almost touches the bottom of the page. Make a large "U" shape, but let the right side of the U open up a bit and taper off until it runs almost parallel with the horizon line. Just be sure it's not straight and curves up slightly before it runs off the page.
Dip the 1-inch flat brush into the water. Wash a pale yellow shade over the entire page to give it some warmth. Don't worry about making it perfect--just make bold, sweeping strokes and have confidence as you work.
Dip your brush into the blue paint. Start at the top of the canvas and make sweeping strokes from left to right and down until you reach the horizon line. Keep the sky color bright, but don't get too much paint on your brush. Add a bit of water to soften the color.
Keep the white spaces free of blue paint to indicate clouds. Keep a bit of yellow peeking out from the blue layer, as well. If you're satisfied, then it's time to move on. If not, just rinse the paint from your brushes under running water, blot them dry, and start over. You can do this anytime to correct a mistake.
Add some yellow paint to the grassy area and the bottom portion where you drew the wide U shape. Add a bit of brown paint to the tip of your brush and sweep upward with your wrist. Lift the brush from the paper or canvas where you want your tall grasses to stop. Use short and long strokes for different patchy areas to keep your seascape interesting. Add a few more shades of brown and darker yellow for shadows to give the beach some depth.
Let the beach and sky you just painted dry, and wash your brushes. Now add the ocean by dipping your clean brush into a rich darker blue in a shade different from that of the sky. Start at the original horizon line and paint the dark shade all the way across. Allow the blue to lighten by adding a bit more water the next time you load your brush.
Keep a few thin strips of white free as you begin to approach the sandy areas you painted. Play with light and dark shades of the rich blue hue until you create a body of water that appeals to you. Make it a bit darker on the side near your grasses and lightest at dead center.
Add a few seagulls by dipping a detail brush in some black paint. Make a wide "M" shape and add as many birds as you'd like, keeping them small. Let your painting dry.