Trying to summarize all the advices based on all previous posts (including mine!):
1) walk only on tiptoe, but at least at 20 km/h: the marathon world record is there then.
2) do at least 40 km a day, but remember that you may be sore and hungry after about 100 meters.
3) don't put anything unnecessary in your backpack, but put everything you might need in case of natural disasters, including alien invasions and meteorites extinction Chicxulub-like events. The backpack should weigh less than 2 kg, but at least 20 kg. If you have problems with the 10% rule, as I have already suggested, EAT A LOT IN THE WEEKS BEFORE THE CAMINO.
4) don't make a fuss with anyone! Total silence! But greet and ask stupid questions to anyone you meet along the way, in hostel, bars, restaurants and cafes.
5) Go for the
Camino Frances in the middle of August, but avoid the busiest time and only if it is winter, raining, hailing or snowing.
6) want to sleep? remember you will find everything full but you can't sleep on the street. Stay wandering the streets all night, never even leaning against a wall. Strictly forbidden!
7) Don't talk to others about politics, religion, sex, weather, family, personal issues, food, current events, sports, cerveza, wine, booze, annoying children and parents, diseases, sorrows, old age, ethnicities, nationalities, dogs, cats, birds, goldfish. And better to be silent instead about what is left.
8) Keep it to the end: you will only be able to pee and do your business in the toielette of the plane for the return trip.
9) you must be TERRIFIED by the
Camino de Santiago, but... come on! don't "overthink" about it: just go to the nearest airport and take the first available flight. The rest...you'll see.
Anything else?