Useful skills

Learn how to pick locks
Learn how to use your eyes also (seeing in total darkness is totally possible)
Learn perfect balance (eyes closed etc)
Know your limits by breaking them (i know for sure (and from experience that people can do so much more than they think they can)
Learn how to go in survival mode (in that mode 45kg lady can lift truck and it can be learned)
Be in shape (lift weights ( i prefer my own body weight akapush ups etc) )
Study some martial arts (i have perfected pekiti tirsia kali / systema / Awud Mied / krav maga and some others)
Learn to shoot (perfect it by shooting 4 hours a day 12years)
Study some languages (Russia , English , French , Japanese , Chinese..... )
Be paranoid (be really paranoid , expect worst , sleep on the floor with bullet proof vest and gun and knife in hand etc)
Take bodyguard lessons (i have taken mine in Russia)
Learn tactical driving (i have been studying in Lapland with Finnish police and in Russia with fsb -really i have)
Study your self an overly good memory (i can tell how many books are in my friends book shells , i know their id numbers , i remember like 4500-6500 phone numbers this time ..... etc)
Take tracing lessons (to learn how to hide)
Be perfect (it is your ass in the line)
Think your self how to improve your actions (like walking it is not so easy as it looks)
Take some acting lessons (to keep the poker face)
Take some NLP lessons (to learn to read the body language)
actually this should be the first step but you have to have good stamina (at least 3500m in 12min -i can run 3750m in that time)
Don´t look suspicious (no ghetto clothing , no bright colors nothing that spots the eye)
Be polite , Be very polite (people tend to remember bad behavior better)
Never think you are ready
Never tell any one your real age (i am actually like 29-34years old)
Start training while you are young (i started in age of 4)
Learn to live by your ear (AKA eyes closed to improve your other senses)
Don´t think i will tell you all that i can do