2. How do you write an abstract?
Identify your purpose. You're writing about a correlation between lack of lunches in schools and poor grades. ...
Explain the problem at hand. Abstracts state the “problem” behind your work. ...
Explain your methods. ...
Describe your results (informative abstract only). ...
Give your conclusion.

3. Key words

4. How long is an abstract in a research paper?
Keep it short. An abstract should be between 150 to 250 words.
According to the APA style manual,

5. Consider your audience.

6. Explain your methods.
Motivation - check. Problem - check.

7. Get feedback from someone.
Summarize your research well.
Try to find someone who doesn’t know everything about your project.
Ask him or her to read your abstract and then tell you what s/he understood from it.