Progress reports are a frequently used and very useful device for staying on top of a long term project. Progress reports are simply put brief reports summarizing the progress you have made on a project to date including an outline of any problems you may have encountered as well as plans for the next work period. If your advisor doesn't require you to submit progress reports, you might consider doing this on your own.
They have benefits for all involved:
There really is no standard format for progress reports. However, given that the peer-reviewed technical journal article is generally viewed as a standard medium for written communication in science, technology, engineering and mathematics, if your advisor doesn't provide you with any specific format requirements, the format for a technical article might be a useful format to adopt in preparing your progress report. Another useful format for progress reports is that of the standard business memo.
Online Technical Writing: Progress Reports.