Tip #2: Accept That Things Take Longer
Accept that presenting and discussing a unit's learning objectives may have taken 20 minutes with that smaller class in the past, and probably takes twice as long with this larger group. Also, you might be lamenting over the days when you could whip around the room and spend a few quality moments with each student or group, or when you could offer immediate and thorough support. Unfortunately, if you did that now with 35 or more in the room, you'd find yourself out of time before coming close to accomplishing the daily learning objective.
One remedy, especially when it comes to checking for understanding? Strategies like thumbs up/thumbs down, or having students hold 1 to 3 fingers on their chest to let you know how well they understand (3 means "I've got it!) Other quick formative assessments, such as sentence starters, can help beat that Time Thief in the room. You can also use exit slips to see if they "got it," asking one strategic question about the day's learning.