Personal Experiences,Study, Learning Blog of Abu Rashid aka Harun

 The following site suggests the use a 50% scheduling rule. We need to have a relatively complete, working version of the software available for testing when we are halfway to a full release. If I want to do a product release 3 months from now, I plan to have a testable version of the product in 1.5 months. The halfway release can be rough and even ugly, but it needs to do most of the things the complete release will do. This rule ensures that the incremental release process can work its magic. You have half of the total time available for finding and fixing problems and making improvements.
http://blog.assembla.com/AssemblaBlog/tabid/12618/bid/2267/To-meet-an-impossible-deadline-cut-your-time-in-half.aspx

mini deadlines for different segments of a whole task.
http://www.smashingmagazine.com/2010/07/28/passing-the-holy-milestone-how-to-meet-deadlines/