I have had a lot of activities which I’ve done with the students this year. We had an English breakfast, where we sang a song and the children had to ask for things they wanted in English.
We also taught the children, at the preschool, a song « We Wish You a Merry Christmas » which they sang at a performance for the parents.
Besides this I have been playing lots of games and using flash cards to teach vocabulary. The children have been really interested in me and so they learn a lot of english by asking me things they want to know and trying to speak to me in English.
So far, they have learned, to some degree, colors, numbers, simple sentences, some animals and emotions (happy, sad, tired, etc)
I think the most important thing is trying to be friendly and developing a desire to speak English out of a natural curiosity.
A huge resource for teaching has been the website http://www.dreamenglish.com