Arise early and stay up late for them - השכם והערב עליהן
One may ask Hashem to punish his enemies only if there is no recourse on earth (as in the case of מר עוקבא). Alternately מר עוקבא added in his studies; he did not daven for his enemies’ downfall.
תוספות maintains that עטרות חתנים is a domed canopy.
This prohibition against עטרות חתנים as well as against עטרות כלות, are limited to חתנים וכלות themselves on their weddings, otherwise they are permitted.
At the time when the מצנפת is on the head of the כה"ג, etc. - בזמן שמצנפת בראש כהן גדול
The מצנפת was worn only by the כה"ג; or alternately he mentions כה"ג (even though the hats of all כהנים are [sometimes] referred to as מצנפת) since the prohibition against wearing עטרות applies only to חתנים who are similar in stature to the כה"ג.