The process of estimating size, time, effort, etc., is fundamental for the success of every software project. Unfortunately, it is often the case that the stakeholders (including project managers, developers, and users) don’t know how to do it properly, and everybody ends up working against the clock to meet impossible targets, getting poor software late as a result. After a short introduction in which I’ll present what can and should be estimated (e.g., time, size, effort, cost, etc.), I’ll focus on what is necessary to get started with some simple, but very effective techniques.