Most people think 'movement' is the thing that's most hard to capture painting outdoors. And it's true. Moving figures, moving cows, moving skies, it's not easy.
But here's a tip:
1) For example, when painting cows, you wouldn't want to add 'the herd' in all at once, rather one cow at a time. It's easier and it will benefit the total more quickly.
2) You can create dots of paint where you would like to add a figure composition-wise), then wait for the right one (color/size) and paint them in.
3) I think it's important to have a strong rhythm of strokes, dots, colors in. See how the total of the painting must benefit from every item's placement and how simplifying shapes can help in creating a strong composition, a strong rhythm of strokes.
I teach about painting Seascapes in ► Seascape Beginner that's here and an online course more specific about Summer seascapes, figures and parasols is this one: ►Painting Summer Seascapes find this here.