First attempt at scratch building.

[MasonJar]

Don't underestimate the value of mock-ups. Cutting up a Cherrios box (or even many Cheerios boxes) can go a long way to helping you determine the final size of your model. You can even glue a photocopy of your plans to the cardboard for a good representation of what the finished model will look like. These mock-ups go together quickly with a hot glue gun, and can be disassembled to provide a cutting pattern for the styrene (just don't use too much hot glue...!).

The only caution I have about mock-ups is don't make them too good, or they may end up standing-in for a long time...

Hope that helps.

Andrew