Best way to tackle “jackets” category is to start with a simple, unlined, shirt-like projects such as this Yves Saint Laurent safari jacket. The cleaner you make it inside, the more refined it will look.

Try make it in a medium weight cotton canvas or denim, finish seams with flat felled construction on long, straighter seams, and bind armhole curves, vents and placket edges in contrast light weight cotton.

If you would like to see more inside close-up, just let me know!