So what kind of guidelines does an artist want?
The flow of the design (straight, swirly, curved, spaced out)
The type of design elements (floral, geometric, swirls)
Design elements (peacocks, paisley, bands, lotus, etc)
Placement on the body (hand, arm, legs, feet)
The mood of the design (bold, intricate, traditional, modern)
When about three or four of the categories are clear, it becomes much easier to apply a design.
Here are photos of a design and the elements that the client wanted incorporated.