I have a subscription at Envato Tuts+ (tutsplus.com), where there are a lot of really good tutorials and courses. The image above was the final product from the course “Creating a Retro Illustration in Illustrator”. The course consists of 7 videos showing you all the details for creating the image while teaching you important skills that can be used for creating other artwork.
This course has enough details so that you can easily follow along. As usual, I had to rewind a lot, but that’s how it is with video tutorials. Most of this course was a review of what I already knew, but I did learn about using the “roughen” effect (under “Distort & transform”) both when creating a brush and by applying it to existing strokes. The use of the roughen effect helps create a more organic look to your artwork.