[Cruisin Marine]

I always did/still do the basics with graph paper taped to the chassis and front panel. Layout the components/ transformers etc and keep moving them about until the feel of the placing is right and best for the overall design.
Mark up with PENCIL on the graph paper.
When you first start, make the chassis oversized until you master this.
The more expensive the aluminium/boxes etc. the quicker you will get there!

Although I can use it, CAD never feels quite right or natural to me, as I like to see it all develop in three dimensions in front of my eyes.
It will be fine for refining for production though, But hey, I may be a old Dino.
A set square is always your best friend of course.