Use any resource that helps you see your work from another perspective. Here is an exercise to help you develop this skill. Otherwise, generally avoid referencing anything outside of your study in the abstract. Start by answering the following questions: What made you decide to do this study or project?
A case study? Will your study perhaps be useful to members of the general public?
A quick read of popular research papers in your domain would give you a clarity on how abstract is similarly structured. When describing your results, strive to focus on the main finding s and list no more than two or three points.
Next, you want to give an overview of your methods. The more important and urgent the problem statement is, the stronger the need for the reader to understand the paper at hand.