System Engineering Concepts: Process Flow Diagrams (PFDs), Work Flow Diagrams, Activity Diagrams, cross functional Sequence Diagrams/swim lanes, Models, Wireframes, Prototypes, ERDs, Use Case, User Story. UML (ArgoUML )and Microsoft VISIO.
Business Value Add on: Business cases, Business Architecture Analysis, Cost-Time-Benefit Assessments, Risk strategies, Gap Analysis.
Requirement Elucidation Tools: Brainstorming, Stakeholder Interview, Story Boarding, Workshop, Reverse Engineering, Process Mapping, Observation, Organizational Analysis, Team Analysis etc.
Other Tools: Contour (for requirement management), JIRA (for work backlog and bug backlog tracking), Team Foundation Server (Smartexcel4tfs for requirement traceability), Windchill (for document review) etc.
Techniques: MOST, MoSCoW, SWOT, de Bono's Six Thinking Hats, SCRS, Modified Five Whys.
Gap Analysis and Quality tools: Histogram, Scatter diagram, Check sheet, Pareto Chart and Ishikawa diagram etc.