Type of index(es):
single concept/name index
several indexes  (i.e., subject/name, subject index, name only, authors cited, Latin plant names, Scripture, bibliographical, or other additional indexes) __________________________

Once we decide to do business with each other, I will ask for the following:

a single PDF of the book after all pagination has been set in stone with India ink glue (=page numbers and content absolutely must not change after indexing begins)
all back matter (glossary, bibliography, appendixes) whether to be indexed or not
all front matter (introduction, title page, table of contents, preface, foreword) whether to be indexed or not
a style sheet, specification/style decisions, a sample index as a model, or permission to make these decisions based on my experience and the needs of the text
copy of the agreement, signed

Even if we simply "Follow Chicago," (Chicago Manual of Style, 16th edition) there are choices available. I am comfortable making the decisions about those items for which you do not indicate a preference.
Style preferences
           Chicago 16 
          House (send detailed Style Sheet or preferred style example)     
           Indented (list style) - up to three levels as needed
           Run-in (hanging paragraph style) - two levels only (main and sub)
           Word-by-Word       Letter-by-Letter      
           Depends on the needs of the text   
Locator Format
           Full page ranges -    324-328
           Abbreviated page ranges (Chicago) -    324-28
           Very abbreviated page ranges (Hart) -    324-8
         Specify alpha-sort order (or let me decide based on the needs of the book):
          nineteen twenty-four
          one thousand nine hundred twenty four
          1924 (i.e., at the top of the index, if a main entry)
         one-hundred-yard relay
         hundred-yard relay     
Cross-reference Placement
          After main entry
          As first subheading after main entry
          As last subheading
          Forbid c/r after subs
           Footnotes, Endnotes
           Illustrations, Photographs, Drawings
           Tables, Charts, Figures 


Some indexing considerations: