Here in Iceland you don't really have to start teaching English until the kids are in 6th grade (12 years old). The rules are that they have to start at that age.
But schools (that want to succeed (so mostly all of the ones I know about)) start a lot earlier.
I have cousins (not the right word for them but stupid English doesn't really have another one for them unless I just use relatives) started in 1st grade (6 years old) and they had no problem talking to my stepdaughter when she first came to Iceland (they would have been 9 years old at that time).
I don't know how they were taught though.
My son just started this year (in 4th grade, 9 years old). I can't really comment on how he's doing since he speaks English just fine now (with English spoken at home all the time).
He is doing some writing exercises (weather, family etc) but not much else.
I used to teach in elementary school a long time ago (the same one my cousins are in (in the asshole of the universe, a town with 1700 people) and what I think made the most difference was that we start early speaking the language in class. Depending on when they start learning it we start using that language as the class language after around the first year so that the kids are not just writing but they get used to hearing the language.
In year 6 (12 years old) English would be the only language spoken in that particular class (unless you need to explain a word to the kids).
The younger you are and the more exposure you get to the language the more you'll learn
