I found that because the students already had an introduction to area, perimeter was not as difficult this year.
We started our notebook section with the usual standard and essential question with pre and post post it notes.
We then added a cute definition found for free on Teachers Pay Teachers.
Of course we needed to add something that related the area to the perimeter. I used index cards and wrote area in bright red sharpie. Then the kids glued them down and wrote perimeter all the way around the edges.
We also did a practice problem on that page. I found a free perimeter practice sheet that had 6 different problems. I made enough copies and cut them apart. So not all of the students have the same image in their notebook.
Lastly we did a irregular shape.
Perimeter was easy this time around, but when we come back to it I know it will be much more difficult (missing side lengths, more difficult irregular shapes, etc.).