Determine the connection between the new teaching point with topics already taught. You need to reveal the connection to students at the start of the mini-lesson to provide a context and allow them to follow you more easily.
Make a list of the main points of your introduction or even write it down word by word. Practice on introducing a topic with a stopwatch. Time is of the essence, so you need to keep the presentation to a minimum and master your speech, so that you don't stall during the mini-lesson.
Mention the rules of the mini-lesson to students and its purpose. The purpose is different from the topic you have already introduced, as it refers to what children will be able to do after the successful completion of the mini-lesson, such as use "wh" questions or how to skim through a text.
Plan the activities that will take place during the mini-lesson in detail. That includes the duration of the activities, whether they are individual or group-based, their rules and the desired outcome -- what you want children to achieve through this task. Explain all these details to students in brief, before the start of an activity.
Sum up the mini-lesson by explaining -- or asking children to tell you -- what you have learned in the last quarter of an hour. Also, write down what comes next after this mini-lesson and use these notes when you are planning the next mini-lesson.