From the Painting Guide: There's a lovely movement in the sky, a sense of bluster, of a storm just finished or moving in. But take another look at where the clouds go behind the trees – they don't show through the branches, but go around the trees. The trees should really be superimposed over the sky. This is something that could've been lost when you repainted the tree tops.

Things to consider:
• Tone: If you're every worried about the overall tonal quality of a painting, it's worth doing a small monochrome sketch first. This'll help you determine which areas should be lighter or darker.
• Shadows: There's a lack of shadows, as one gets on a dull day, but this is contradicted by the blue pieces in the sky, which suggests the sun is coming through, and the light behind the trees on the left-hand side.
• Horizon line: The horizon line is right in the centre, cutting the painting in half. If it were lower down, you could paint more dramatic sky and if it were higher up, the road loading down to the sea would gain more emphasis. Also, though it's probably just the way the photo was trimmed, the horizon of the sea isn't quite parallel to the top and bottom edges of the painting, it goes up on the right-hand side a bit.
• Scale: Look at the signpost, the trees, and the house. The house seems quite close, but it can't be given the size of the signpost (unless it's a tiny beach cottage).