Use Clear Rubrics
Rubrics provide scoring or evaluation guidelines for assessing student work. It clearly indicates the criteria you will use to assessing student performance, including clarity around different levels of quality in student work.
Thoughtful and clear rubrics identify your expectations regarding the quality of work you seek from students. They also permit students to be more cognizant of the quality of their own work and that of their peers as they evaluate the quality of their work against the rubric.
Although it takes a little bit of time to construct a rubric it reduces the amount of time you spend evaluating and responding to student work. You can draw on language from the rubric to incorporate into your feedback which can save time.
For more information about how to create a rubric, visit Rubistar at http://rubistar.4teachers.org/index.php or Google "rubric creation in higher education" for many more resources.