Hi guys I have been considering this myself as I really fancy a 21mm gauge layout, nothing fancy you understand, just something very simple to start with.
One bit of advice I can give since I have build some 009 track work and that is don't rush the first point or section of track.
The second bit of advice is to build some cardboard jigs for the track and point work, cardboard from the wheatie bangs or other breakfast cereals is good enough for this.
For best results use a bit of 9mm or deeper plywood as a base for the give me a few days to sort all this out and I will try try and do an article on how to build track over Christmas.
I have been using David Lindfield for the last few years. He is very good and will give you some great advice. He did all my track work and recently did all the lighting for me.