vB3 Hacking 101 Guide

[Ninth Dimension]

TBH all I'm looking for is a very basic guideline so I know what to do, and what not to do, for example I was looking at things like

PHP Code:

define('NO_REGISTER_GLOBALS', 1);
define('THIS_SCRIPT', 'vbindex'); 


and I'm not sure what they are for...

I'm also interesting in knowing what's the best way to do queries and pull templates, I mean I can learn from some of the other hacks that have been released, but then... what's to say that the hack i'm looking at have been done in the best way?

I hope that someone does sit down and write a guide, just very basic stuff, and I can pick up the rest myself