Have you tried talk partners? Get them to sit with set talk partners (pair high and lows, chatty and less chatty etc) and regularly get them to discuss ideas with their talk partners. Then brainstorm the class ideas on the board. Also, especially in things like phonics, practising writing letters on each others backs, seeing if the partner can guess what letter it was. Having them sat in a circle, with lots of resources in the middle for demonstrations can also help keep them engaged. As can a 'no hands up' approach, where you pick lolly sticks out. If the children think they might be picked on at any time, it might make them concentrate a little harder! When I was in year 1 and my class were a bit dozy, I would make them do alphabet or counting head shoulders knees and toes. So instead of singing the song, do head shoulders knees and toes but with the letters of the alphabet, or in maths you could count on from a number, or count in 2s/10s. This gets them active, and they love doing it too hope that's given you a few ideas!