Grant applications, research articles, science reviews, conference presentations: they all need an abstract. Getting that abstract right is extremely important – it should be a summary of all the key points.
But it can’t be a grab of some key paragraphs from the main article, or written as an afterthought: it has to be carefully constructed. It has to be punchy, with a beginning, middle and an end. A good abstract tells the reader in 250 words all that he/she needs to know.
A good abstract makes the reader excited about reading the full proposal or research article, or attending that conference presentation.