Every project is unique, and the estimation technique that works once won’t necessarily help at all next time. The Project Management Guru is here to help by identifying the different estimation tools and techniques, so that you’re never stuck using the wrong one again.
First, there’s analogous estimating, which means you use experience from previous projects. There’s also 3 point estimating, which involves the analogous method but also calls for three different estimates based on the best-case scenario, the worst-case scenario, and a scenario in between.
If neither of these techniques seems right, try consulting an expert or doing an estimate based on published data. You might also need to construct a project simulation or estimate backwards based on the project end date. Some projects will be easier to estimate than others, based on whether your activities are stable or dependent on other variables. Do whatever works for you, or try a combination of techniques. No matter the estimation problem, the Project Management Guru has a solution.