I started my layout around 1997 as a 4 x 8 layout. I later expanded it by adding another section that's about 4 x 8 and makes the layout into an "L" shape. Below are pictures of the layout as it evolved. There was a lot of learning going on throughout all of the construction which I put towards my Z scale layout and other projects.
Click the images below to see how I build various areas and how to improve different elements of your layout.
Building the Main Station
Building the Extension
Building the Suburban Station
Hoboken Terminal Construction