1) Use the radio!
2) Do overhead joins!
3) Keep a good lookout!
4) Use your brain!
Personally, I think your list is in the wrong order. I would prioritise as follows:
1) Use your brain!
2) Keep a good lookout!
3) Do overhead joins!
4) Use the radio!
Although to be fair you didn't say your list was in order of priority, I just read it that way.
But, in general, I feel that there is too much reliance on radio in the UK. Judging by the amount of "What backup radio should I carry" threads on here I presume I'll be in the minority
