Hi, I don’t speak English at home with my son, however he does
I would say reading. We also encouraged him to keep log of words he does not know the meaning of when he reads and look it up in the dictionary. It is quite hard at first - he was not excited, but now he really enjoys it. He uses his IPod touch
We test him later. For English comprehension - do Bond papers and also VR. Start with the easy ones and review. Right the words down, etc. He will get used to it and will build up the vocabulary. If you consistent – you will see the results pretty soon. It also helps to get an English tutor or someone who can help and review the papers with your son.
A friend of ours helped a lot to discuss the meanings of the words, etc. Some Indie papers use test from the classic English Literature that can be quite challenging even for native speakers. Hope that helps.