Here is a list of tasks you'll need to work through with your project. Spread them out between now and the due date with intervals that make sense for you.
choose your topic
organize your notebook
ask organizational questions
research your chosen topic
define your problem
develop your hypothesis
design your experiment
Turn in an experiment summary to your teacher or mentor (if required, and even if it is not, I still recommend you discuss your experiment with someone)
Gather all the materials you need for your experiment
Start your experiment
Setup an outline for your project report
Collect materials for your display
Draft your project report
Design your display
Finish your experiment
Revise your experimental procedure and equipment list as needed
Analyze your data, drawing conclusions
Revise your project report
Complete your display
Edit and produce the final draft of your project report
Prepare for the fair!
This list is based upon the tasks you will need to cover for the typical science fair – you can, of course, add or subtract from this list as you want (and as your specific fair rules require).