I have to say looking back on the first PCB layouts. My skills have a quite a bit of improvement Between versions of PCB layout. In Planning out sections of the board and optimizing placement of components. Quite a bit of things you should plan out before even thinking about doing the traces.
My first designs were so Simple the autoroute worked perfectly fine. But soon as I added complexity too the placement it would eventually give up on completely routing. I brushed up on manual routing and common good practices. I found the use of a auto router is a good base for starting manual routing. Then doing manually is just like putting a puzzle together.
I also learned about using Copper infill and Ground planes for the Double sided PCB and why it cleans up quite a bit of the grounds and +12v Rail. Before using these Manual routing started to become a nightmare becoming quite the rats nest of wires.