well other than telling you there are lots of things you can read about picking, I will say as far as tension you should start with none and feel each pin.
After that start putting as little pressure as possible on the wrench and go back and feel each pin. You should feel one or more that act like they are rubbing or move a little and get stuck. like imagine when you push up on a pin with no pressure it feels like ___ that...ok well if the pin is binding it should feel like --- how it kinda catches and stops and starts to move, also when you press on that pin that feels stiffer than the others try lifting the pin SLOWLY as you increase the tension...if it binding it should stop lifting and it should click when you let off tension....
well I suck at explaining stuff but I like trying
so take from that what you can and also try reading...
MIT guide to lockpicking
