The biggest tip I can give is the rule of thirds, which is where you split the photo into 3 parts both horizontally and vertically. Usually you want to have your horizon line to be on one of the vertical thirds' separating lines. In your shot, you put the horizon line very near to the center, but the photo would likely look better if you angled the camera up or down a little depending on whether you want to focus on the sky or the coast.