What image characteristics is best for Illustrator when using Image trace?

What image characteristics will give me the best results when using Image Trace?

my goal:

• to achieve the most simplified and optimized curves (path and anchor points) possible

When talking about image characteristics, I am curious to know what type of images Illustrator can handle the best.

For example:

1. Blueprints
2. Drawings with outlines
3. or just flat shapes with solid colors and no outlines at all
4. etc. etc. 
   
   Thanks a bunch for any ideas, hints, and recommendations.
   Appreciate it!