I like to start a watercolor with a light grid to keep my parallel lines parallel. I start with a pencil sketch and then go on to pen and ink.
I tape down all of my watercolors to get the white edge of the paper. Don’t think you need anything expensive. I use carpenter’s tape, but it’s only there for a couple of hours. I wouldn’t leave it there for more than a day.
This is the white edge I’m talking about. When the tape is taken off, you have a white border.
Click Here is a really short video of the painting site.
Madrid is great!