Stretch a lot. Then just practice everything you are taught literally two thousand times, slowly. To start off, do a movement but stop after a centimeter. Check you are in the right position, are your hips and shoulders facing the correct way, should you be twisting, where should you hand be, what position should you feet be in, should your back be extended, every single thing. If you do not remember every thing, ask your teacher to hold techniques and write down his positioning.
Move another centimeter, check again. After 50 times, stop the technique once half way through, check it, then finish it, then check it. I would say after 500 very slow techniques, start to speed it up. This may seem boring but you should be dedicated. Some people naturally learn quicker, but someone's natural ability will never beat dedicated training. How are you for spare time? When i got serious with martial arts i would go to a woods somewhere every morning and train for 3 hours.
Do not be worried about moving slowly, if you technique is slow yet perfectly executed, your teacher will notice. Also if attention to detail is a problem, execute a movement with your teacher watching, write down everything he says is wrong with it.