Tutors for Adobe Illustrator flat sketching?

Everyone is giving some great advice and support. When I started learning Illustrator in early 2000’s my work was not very good. One thing I can share is what helped me grasp building flats, tech packs and prints was to work with simple existing files or templates and work backwards by clicking on layers (in PSD) and lines (in AI) and seeing how they were constructed and connected. Best of luck! It sounds like you’re on the right track!