Building Software is more than only following business process definitions. Our Users are not robots, they are rather anarchists when it comes to getting their work done. Thus enterprise software is a myth, meaning, one can not use one transaction to perform many tasks due. Knowing that, what we build, can do more than only serving one task, one step in a BPD (business process definition). We do base our softwares on a few, but powerful methodologies:

• Agile Software Development (Kent Beck was one of the first promoting it)
• SCRUM, an approach to get work done and being scientific at the same time, a role play game, essential for on-site projects
• One of our paradigms are Finite State Machines, please read this article too 

With Agile we do share the same credo:

• Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.
• Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage.
• Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale.
• Business people and developers must work together daily throughout the project.
• Build projects around motivated individuals. 
• Give them the environment and support they need, and trust them to get the job done.
• The most efficient and effective method of conveying information to and within a development team is face-to-face conversation.
• Working software is the primary measure of progress.
• Agile processes promote sustainable development. 
• The sponsors, developers, and users should be able to maintain a constant pace indefinitely.
• Continuous attention to technical excellence and good design enhances agility.
• Simplicity--the art of maximizing the amount of work not done--is essential.
• The best architectures, requirements, and designs emerge from self-organizing teams.
• At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly.

Building motivated teams we would consider the key to successful projects and defining a life-cycle of roll-out, or "getting the baby alive" is important even more so!

Consider it a "pregnancy":

• The wife carries the newborn for nine month
• There is a time window of plus/minus 2 weeks to get it delivered
• The real works does start after...  

Still preferred reading: "The Deadline" by Tom DeMarco