trial and error brother. it's always nice to have a scratch box of your own in your lab. trying different things in an isolated environment. this is a constant learning exercise. i think security in general is like art of war by sun tzu (i was flamed so hard before on securityfocus for saying that ) but i honestly believe it is just that. we have to evaluate and train our minds to understand what others are thinking to protect and perhaps defeat, or retreat. rather then picking up "some hack book", what i did was read alot of manuels back from the phreaking days, and i've just never stopped reading the basic manual on how to do things.

for good reading material, i would check out cert.org or sans.org. you could always find interesting things to read at most university's research site. you have to remember, most of their courseware, at part comes from many governmental projects, etc...

-w0rm3y