My both horses came to me with their feet never cleaned. Meaning they didn't know how to pick up at all and never had feet trimmed (both were 1.5 years old). I started with putting rope above the hoof and lift it up with the rope. As long as they picked it up I let them go and gave a carrot. After couple days I started to pick the hoof up with the hand. The whole training was certainly not 1 day, but took lo-o-ong time (and was real pain in butt - I thought I"ll NEVER be able to train them). Now one of them is voice trained to pick up, for other one the lightest touch is enough to give the hoof.
Actually, I read one more thing on my way of training. When you pick the hind foot, don't try to pull it and clean it right away. For some horses you need to pick it up and hold for couple secs so she can relax it before moving the way you want it. My older one likes it to be this way. If I drag it right away she may try to release it, which looks like light sideway kick. Not all horses need that, but some certainly do.