It's tempting to jump in to painting the demo but please watch this first! Knowing all about water and how to extract potential from your photos is key to creating better art.
Sort your photos and clarify visual intent. Even if you copy my reference exactly, start collecting photos for future projects of your own. Ask yourself what is a good photo. start to combine simple studies (dot studies, or plein air sketches) and photos to make a better painting.
SAY NO TO FOCAL POINTt: I don't like the term 'focal point' as this seems confining to me as I create. The focal point might shift as I create my painting. I like all options open while I create. A FOCAL INTENT is a better thought. This will help you sort your photos, gather reference, plan for color harmony and make the best choices as you paint.