Digging a little deeper, the 12 risks are, in approximate order of danger:

1. failure to understand software (e.g. process, costs, expectations)
2. failure of team dynamics (e.g. dysfunction, lack of trust)
3. failure of roles (e.g. realizing that software can never be completed without testing)
4. failure of resources (creative, productive, effective people are rare)
5. failure to specify (i.e. to understand, communicate, document the problem domain description)
6. failure to architect (i.e. to create a solution that fits the problem)
7. failure to design a software application (i.e. ad-hoc spaghetti design)
8. failure to implement the software (unmaintainable spaghetti code)
9. failure of quality assurance (reliable software results when testing time equals development time)
10. failure of project management (e.g. management that demoralizes and robs the team of productivity)
11. failure of technology (i.e. to select reliable technologies before the project starts resulting in technology churn)
12. failure of tools (i.e. to select good tools before the project starts)

Some success factors are: Grasping the level of effort, Integrity, Team Leadership, Team Dynamics, Technology, Tools, Requirements, Design. Click here to find out how to reduce these software risks to a minimum.