When painting plein-air or as some say painting on the spot, I teach my students to try and not change a thing about how they normally paint a watercolor. Yes there are things that are different between painting plein-air and painting in your studio, but the trick is to try to make both the same.
Use the same brushes, and palette and bring your camera
so you can use it to focus in on a scene.
The biggest problem most first-time plein-air painters have is putting to much into their paintings and trying to follow the changing light. The trick is to do a small thumbnail sketch or take a photo of the area that you want to paint, then start and stick to that thumbnail sketch or the photo. Don't change the shadows or lighting half way through and then try to finish it with a totally different light.
Something else you can try instead of plein-air painting a scene is to do a fast watercolor sketch of the scene. Then take that sketch and photo back to the studio where you can then paint a studio painting of the sketch and photo.
Another good rule when painting outdoors, don't paint with the sun hitting your paper, find a place in the shadows or angle your piece so the sun is hitting the back of your paper and your painting surface is in the shade.
Don't
forget the things you normally would need outdoors like, bug spray, sunglasses, hat, water bottle, and anything else you normally would use outdoors.
