Get your students up and moving. If your pupils are sitting at their desks for a long period of time, they are bound to become antsy. Keep their focus by having them stand up and do a few jumping jacks together, by teaching them a clapping game to remember a math rule, or moving everyone over to the "library" area of your classroom and teaching your lesson there.
Implement a daily snack time. You've probably noticed that students tend to lose focus before lunchtime and at the end of the day when they are hungry. It isn't easy for anyone to concentrate when all they can think about is their empty stomach, so implement a snack time. Eating a snack will boost your students' energy and help them to gain their focus back. Ask parents to provide a snack for their children each day to avoid having to keep tabs on everyone's dietary concerns.
Ask your students questions from your lesson. When you're teaching a lesson to your class, it can be difficult to hold everyone's attention. If your pupils know that you will ask them questions, they are more likely to listen to be able to have a response for you. You can also ask the class as a whole a few questions about your lesson, such as to write about something they learned from your lecture and what they liked the most about it. Have the students turn these papers in for a grade.
Provide positive reinforcement. Everyone likes to hear when they're doing a good job at something, including your students. If a student gets a perfect score on a spelling test, praise her. Or, if another student has drastically improved his math skills, take him aside and let him know that you've noticed how hard he has been working and how much he has improved. This will make your students stay focused, because they know you're paying attention to their progress.