For beginners, 'Addicted' is a great start. It has a relatively straightforward plot that is easy to follow while still being interesting. It gives a good taste of Zane's writing style.
I would recommend 'Skyscraper' as well. It doesn't have overly complicated language or a convoluted story structure. The characters are well - developed, which helps new readers get into the story quickly. Moreover, the themes it explores, like ambition and love, are quite relatable.
A good option could also be 'Shame on It All'. It has a clear narrative arc and characters that are easy to empathize with. The story unfolds in a way that draws the reader in, and it gives an introduction to Zane's ability to handle family - centered dramas and relationships.