Your project doesn't have to be complicated and the display board doesn't have to be fancy. Just neat and easy to read. Judges look for (1) how well you understand what you did. (2) how carefully you collected and tabulated your data. (3) Did you do your experiment more then once as a check against errors you might've made and also if you are taking measurements you can average the data by running your experiment several times. (4) what thoughtful conclusions you make about your results.
Sciencebuddies.com has some interesting science fair ideas that are reasonably priced. You may also want to look at ehow.com.
death
Niger.
It may very from fair to fair but some common things include an explanation of what you did your experiment, why it happened (the science behind it), and practical applications.
what are some catchy titles for sience fair projects about milk
A volcano or Christal
structures
The grade is up to how diligent you are. Below are some sites that have lots of science fair projects.
A science fair logbook is just a notebook where you keep track of the work you have done on your science fair project.
i need a friken science fair project
physics science fair still models
what can i do with yeast for a science fair project