Nearly always out, in the woods walking the dogs , then almost without realising it i'm singing a tune in my head , sometimes i record it on my phone whilst in the woods and hope no one walks round the corner whilst i'm singing into my phone , i have done whole songs in my head before , and forgotten them before i've got home !!!
a few times i've just played stuff on the guitar and thought , yep , thats a song. but i dont have a set method at all.