I broke into this place with my friends and I cracked the window of the door and put my hand in and turned the knob and got in. The door was right near a corner, and the wall next to the one the door was had had one of those security panels that look like long calculators right near the door. I walked past it and it went off. How do I avoid it going off next time?

what color was it?, if it was grey or light brown it could of been a magent housed in plastic

i think it might've been grey but I'm not sure, it was dark.

Clip wires Disconnect the Plug or bash the mother fucker with a hammer were was it excatly

Clipping wires will notify the security company, clipping power will only cause the battery back up to come online, which all security systems have, even crap home ones.

I'm not quite sure what kind of "security panel" talking about here specifically. If you mean the wall contorller with all the buttons, thats not what set off the alarm. What did set it off:

Passive infared sensors (most common type of motion detectors) would be the worst case. Only tip for you on that: glass is not transparent to infared, block the reciever with a pane of glass maybe, or avoid it. These things are near impossible to defeat though. Avoidance is the only real way, maybe you can come up from behind and block it with the glass I mentioned, other materials may be transparent to infared.

Your typical door security would be two boxes. The one attached to the wall has a little magnetized needle with a spring. The second is on the door, it is a somewhat powerful magnet. The magnet keeps the pin from being pulled back by the spring, which closes the circuit, triggering the alarm. To cicumvent this, it should be obvious, you would take your own magnet and place it on the door side of the wall box to hold the pin in place. I don't feel like typing out how to figure out the correct poles, but, needless to say, you gotta put the magnet the right way to attract the pin, rather than repel it, which would set off the alarm.

This information is freely available on the internet, how alarms work etc, I'm not responsible for what you do with it.