This is just one image from the digital stamp set Dragon Beach Fun by Dustin Pike. I love the beach so this just jumped right out at me. The striped background paper is also a digital from paper pack Oh Boy, I feel like it gives out a beach towel vibe!
The image was colored using Copic Markers.
First dragon:
BG10, BG13, BG15, BG32, BG49, V00, V0l
Second dragon:
G0000, G00, G02, G03, YG7,YR23, Y23
Sandcastle:
E34, E44, E42, E43
Water:
B02, B05, B00, B14
Clouds were created with an ink pad and stencil.