Make sure that if you over-spend on some tasks, that you under-spend on others. In this way, you can control your spend and deliver under budget (or at least meet it).

Whether the requirements for your project were to install a new IT system, refresh a website or consolidate data centers, your project needs to produce solutions which meet these requirements 100 percent.

The trick here is to make sure that you have a at the beginning. If the requirements are ambiguous in any way, then what was initially seen as a small piece of work could become huge, taking up valuable time and resources to complete.