You've just taught a lesson and actually you're feeling pretty good about it. How do you know if your students got it? Just what did they get out of?
Exit slips are a quick way to check for understanding. Give your students a 3x5 card at the end of class - allow about 5 minutes for this. Give them a question to answer that will show you their understanding of your lesson. On this website, click on the assessment tab and there's a rubric to use to assess their reflection. Of course, you always give students the rubric ahead of time so they know your expectations. Use their responses to design your next lesson or to see which students need extra help.