The first tip for teaching is to be adaptable to daily circumstances.

Teaching Pacing: It’s Never What You Expect
However long you think the lesson will be, it will rarely turn out that way. I have planned lessons and made elaborate PowerPoints that took me four hours to create. I thought the presentation would take two hours to deliver, but ended up taking up a fraction of that time. Likewise, I have built lesson plans where the class is only able to get through a couple of the objectives because of great questions and discussions. You have to be ready to adapt your lesson for the class.
Be Ready to Fill Time
You might have to fill time. I like to come up with a few activities that I can use if I am ahead of time. There are many fillers. Current events related to the class can be one good filler. You can also find articles that fit with the class to have students read and discuss. YouTube and other multimedia sources can be used to supplement the classroom content. If you find great computer-based content, you can use it as a filler if you are ahead of time in class, and use it as additional resources or homework if you don’t need it to fill class time.
Adapt to Your Students
Also know that whatever you plan might not work when you are in the class. Just because something worked really well in one class does not ensure that it will work in another. The composition of the class, the time of day, student attitude, and many other variables can affect a lesson’s success.
The pace of the class will be greatly affected by the students. You need to constantly monitor students for understanding. If it does not seem like they understand then ask questions. If the class does not have prerequisite knowledge, stop what you are teaching and back up until you feel like they understand. If the students understand a concept, they might be ready to move on to the next topic. Don’t belabor something they understand. If you lecture, the students will reach a saturation point. Switch to a more interactive classroom activity or start using questions to increase student engagement. When the students are getting fidgety or seem like they need a break, then take a break. Plan ahead, but be adaptable in your delivery of a lesson.