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.

Pen & Ink La Almudena Cathedral 

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.

A small watercolor taped down to the drawing board.

This is the white edge I’m talking about.  When the tape is taken off, you have a white border.

Small Watercolor of Almudena Cathedral June 24th 2018

Click Here is a really short video of the painting site.

Madrid is great!