Sorry if I'm necroing a bit but I have a few tips on this.
1) Be gentle on the tension wrench. It's easy to over torque especially when you are first getting started.
2) There is a difference between a rake and a pick. Using a rake is a good way to "prime" the pins, but in cheaper locks can pop it in less than ten seconds.
3) As Wolf stated, using an electric pick is way too loud to be practical. Unless the place you are trying to get into is VERY remote it is best to avoid using an electric pick.
4) Bump keys are a good way to jam a lock and doing this often leaves behind evidence (damaged pins) that prove the lock was brute forced. The idea is to get in and out without being noticed.
5) If you are getting past physical security of any kind or hacking a computer on-site it is best to have someone you can trust with your life watching out for you. It's easy to get ambushed by security while you are concentrating on a challenging task, having a wingman watching for you and communicating via encrypted shortwave radios nearly eliminates this risk. Word to the wise though, two is a party three is a crowd. The more people you have the more likely you are to get noticed. I never work on-site with more than two other people.
6) Lock up after yourself! On your way out lock everything back, picking works both ways and if the door is locked when they come back they likely won't notice that their computer has been compromised (if you covered your tracks).
7) Learn and understand military/law enforcement raiding tactics and adapt them to what you are doing. Preparation is everything, spend weeks preparing for a two hour on-site and you likely won't get caught. Rushing in blind will get you busted.
Any-who, just a few tips for on-site hacking; hope this helps someone. Probably best not to try it under real world conditions unless you really know what you are doing though.
Sources: Military training, security consultant work, common sense.
Addendum: If you guys are interested I could do a series of physical security penetration testing tutorials. It's an interesting subject for study and there are definitely parallels to computer security pentesting. Just a thought, let me know if there is an interest.