Keep your personal life in order. Get lots of sleep, eat healthy, and take vitamins - especially if you have an iron deficiency. Stay away from "the drink" - if you know what I mean. And remember, "Both Wine and Women can lead a wise man astray."

Also, create templates of your code and a "code generator" that works using regular expression patterns. IF you find yourself copying and pasting, then searching and replacing similar classes, automate this process. I did this for my PHP projects, in which I can create a CRUD application, complete with all the basic MVC components, based off my data tables - the data models all look the same except for the data tables they represent, so these are setup in templates and used to generate my initial code. Saves hours of typing.

Finally, tell all people involved with the project that the code is going to take 1/4 to 1/2 times longer than YOU think. Negotiate more breathing room for yourself, early on. "Late" is a relative term. When changes occur in the project, mid-stream, let everyone know up front that 8 more hours of work has been added. A tracking system, such as one offered in "FogBugz" might be helpful to yourself and managers to anticipate how long its going to take to get something done, based on previous experiences. I try to take the tact, "It wasn't late - I used the proper amount of time it takes to complete this function - it merely took longer than we expected."

Another programmer may say, "Well I could have done it faster..." Maybe, maybe not, that's not a point worth debating or beating yourself up about - there's always going to be some "smart" guy trying to push that button. He'll slow you down if you think about it! Its always a bad situation when its your boss, though. At that point, I'd consider looking for another job, cause that sort of boss is an arrogant JERK, in my book.