Awesome start! You had mentioned to me in your post that you were giving watercolors a go, good stuff :)

I said in my post and I'll reiterate here. My best rules for myself are light to dark, background to foreground.

Easy enough right? lol

I usually squint my eyes to get rid of as much detail as possible so that I'm only looking at the image to find the lightest lights and darkest darks. I'll slowly open my eyes to reveal more information but I try to keep the "big picture" or "simplest idea" in my head as I start to paint. Watercolors add pigment so if you've got a highlight or a really lit up plane you definitely want to be careful about adding color there because once you lose the white of the page your highlights are gone. When you're in the sketch phase it's a good idea to mark out a few areas where your "super highlights" are going to be and be sure to save them when you're painting.

I'm a rambler so I'll stop myself. Ive followed you so I'll be sure to check in every so often to see what you're painting up. Thanks for popping over to my blog, happy painting! :D