XMPP Programmer's Tips and Tricks
Having a Jabber client available that has a XML console is a really good thing! In example Exodus has a nice console (press F12), but there are many other possibilities, too.
For C and C++ users
Xerces-C is a good xml parser for xmpp. It may be a bit heavy, but it supports sax and dom.
Windows GUI programmers
Do you know about blocking and non blocking sockets? Do you know WSAAsyncSelect() and threads? No? Then you should consult in exmaple tangentsoft's wskfaq first!