Hi Miss Mary,
Assuming this is a 1-2 hours class:
You could try grouping the children into 3 or 4 groups based on age/ability
Each lesson start with a warm-up game.
Remember that the older children can help the younger children and the younger children will learn by listening and watching.
Organise each day so that you see 2 - 4 groups for 15 - 20 minutes each.
For each group have a learning intention and you can do some really concentrated learning. Just bring them down into a small group on the floor or at a round table and teach them. At the end of their INSTRUCTIONAL LEARNING SESSION you can give them a worksheet or activity that will help them practice the lesson. Following this they will have a special project to complete for you to demonstrate an understanding of the concept (like make a song, make a game, make a worksheet, put actions to a song (if learning verbs) write a story with picture that they then get to read to the little children etc.
In this way while you are teaching one group the other groups are continuing with their work.
Between each group you will need to go and see the little ones (or hopefully you will have a helper in your classroom that can help them work on their projects).
Finish each class with a whole class warmdown where the children get to demonstrate what they have learnt that day.
The kids love it because they can say "Today i learnt how to ..." and then they give an example or show their work off to everyone.
It takes about 2-3 weeks to get children properly settled into this type of routine. It also takes a lot of pre-class planning time - but it is definitly worth it! I usually instigate this type of classroom with a behavioural plan that rewards children for good behaviour.
Remember during your group to look up every 3 - 5 minutes and CATCH SOMEONE BEING GOOD.
Hope that gives you some ideas. If you want any more information or follow up activities just send me a message or email.
cheers
Vicki