Je n’ai fait celle-ci plus longue que parce que je n’ai pas eu le loisir de la faire plus courte. [I have made this longer than usual because I have not had time to make it shorter.]— Blaise Pascal, 1657, Lettres Provinciales
Whether for a conference presentation or a journal article, the abstract is likely to be the piece of text that first gets people to pay attention to your work. Abstracts are necessarily short. As Pascal knew, it takes a disproportionate amount of time to communicate concisely without messing things up.
Nature — one of the most famous science journals — have provided guidance on how to write a good abstract. They call them summary paragraphs, but it amounts to the same thing.
The following Word file (please do feel free to download and use it) is a template to fill out prior to submitting an abstract to an academic conference. Nowadays, abstract submission is almost always done via a web form, and as lead author, you’re expected to have the sign-off from all collaborators (which includes supervisors) prior to submission. That means that you and your collaborators will want a written record, and to have agreed on things like keywords to be used for the submission. You may want to add more details, but these are probably the minimum you’ll need.
More than anything, remember that your abstract should be written for your audience, to draw their attention to your work. Therefore, it should be aligned to their interests.