First and foremost, you need to know what the SEO consultant is working on each month. Ask for specifics on tasks and closure of any known deliverables.
Second, I would also ask him to send you reports or generate your own reports. Here are some of my favorites:
Google Analytics
Visitors
Page Views
Bounce Rates
Pages Per Visit
New vs. Returning Visitors
Traffic by Channel
Traffic by Source
Traffic by Social Media
Traffic by Referrers
Top Search Queries
Top Landing Pages
Most Popular Pages
Top Exit Pages
Conversions by Goal
Conversions by Medium
Revenue by Channel
SEMrush
Domain Overview
Positions with Changes
Top Pages
Competitors
Site Audit
Link Audit
SpyFu
Domain Overview
SEO Overview
Page 1 Keywords
Almost There Keywords
Pages 2 to 5 Keywords
