I am somewhat active already. I bike everywhere (when my bike is not stolen that is! Grrr.) Attend the gym on a regular basis (at least three times a week) where I spin, do cardio and lift weights and every now and then I also crossfit. So it is fair to state that my overall condition is not excellent but also not too bad. Since I don't believe in walking the Camino before actually being in Spain I have focused on walking at least six kilometres every second day or so the last few months. So basically not overdoing anything. Besides that I have tried to get stronger since I figure I will need muscle mass in the legs obviously but also in the upper body due to the fact that I have to carry a backpack where most of the weight is placed on the hips/lower back. Apart from that I haven't done much else so I hope that will be sufficient. The last week I have started walking longer (roughly 10-13 kms everyday) with my backpack to get a sense of what it will be like. So far I haven't experienced any blisters, pain or other unpleasant things so I am quite certain I am prepared and luckily I am very stubborn so I am not likely to give up simply because of a few blisters and sore feet.
Only two days to go and I am very excited. :-)