If your rubric has a limited number of concepts, you might consider using color coding. As you assess student work, you use a certain color highlighter for each major concept in the rubric (for example, for writing, red for thesis and topic sentences, yellow for evidence, green for details, etc.) When you see a strength, you use that color marker to put in a Plus(+) sign next to where you highlight the actual strength Likewise, you can put a minus (-) sign next to a learning gap such a sentence that is missing a transition and indicate where the transition should be. Since each color corresponds to your rubric, you do not have to write out the type of learning strength or gap. You indicate the category by its color and then you can write a formative feedback comment more quickly.
A variation is to use a certain colored highlighter for above proficient (green), proficient (blue), developing yellow), and beginning (red) levels in the student work. For example, if students write an introduction at the proficient level, you highlight it in blue. If their conclusion lacks a restatement of the thesis, does not include the categories of proof, , and does not have an extender, you highlight it in red. Students can do a color scan of their papers to see their levels of proficiency.
Help your students to improve by adding color to their work
My book, Formative Assessment: Responding to Students, is available through Eye-on-Education.
Education with Technology Harry G. Tuttle 
