Get something like a spiral notebook and use it to log attendance at meetings, anything you do for a project, any ideas you contribute, etc.
The reason for the log is that you will eventually want me to write a letter of recommendation for you. The strength of that letter will depend on how much you are able to contribute. You will want to make sure that you get credit for every contribution you make. So when you ask me for a letter of recommendation, give me a copy of your log. I will use it to give specific details of what you did for the research program in your letter.