High-level process requirements
Use 1-2 day workshops to define high-level business processes that you want to see in a SaaS product. Avoid the traditional exhaustive requirements approach used for on-premises software.
Trial period product evaluations
Product evaluations should not be based solely on demonstrations. SaaS solutions must be able to meet your requirements using sample data during a trial period as a proof-of-concept.
Iterative approach with short cycles
Adopt an iterative project management approach based on short cycles and early deliverables (pilot quickly, change later). When it comes to SaaS, agility trumps methodology.