If you do a YouTube search, you will find many videos on how to knead dough by hand, although most such videos that I have seen tend to be with respect to bread dough rather than pizza dough. However, when I hand knead pizza dough, these are the basic tips that I use:
1) Sift the flour, for improved hydration.
2) Work with manageable dough batch sizes. What is a manageable dough batch size will vary from one individual to another, based on hand/arm strength and other factors.
3) When using a high-gluten flour, use a hydration that is commensurate with the rated absorption for the flour. For example, for a high-gluten flour with a protein content of around 14%, use a hydration of at least 63%, and preferably a percent or two higher.
4) When working with doughs made from high-gluten flour, which are harder to knead than doughs with less protein (King Arthur says to use a machine for high-gluten flours), let the dough rest from time to time during the kneading process. This will improve hydration of the flour and it will allow the gluten structure to relax, making it easier to knead the dough.
5) Unless the dough recipe specifies otherwise (e.g., a classic autolyse), if using salt and/or oil in the dough, add them to the water, not to the dough being kneaded. This will make incorporating all of the ingredients easier and more uniformly, making kneading easier.
6) Avoid excessive kneading of the dough. However, the dough should be kneaded sufficiently to develop a gluten structure that will capture and retain the gases of fermentation over a prolonged period. The degree of gluten development should be less than with bread dough, which usually requires full development of the gluten. With pizza dough, greater reliance is placed on biochemical gluten development. In this regard, see the Lehmann PMQ Think Tank post at http://thinktank.pmq.com/viewtopic.php?p=34193#34193
7) When working with high-hydration doughs, use a bench knife, or even two of them, to handle and turn the dough during kneading. This will help reduce incorporating bench flour into the dough. Using wet hands or hands dusted lightly with flour will also help handling the dough.
Another hand kneading technique that I often use, usually for fairly high-hydration doughs coming out of the mixer, is the one shown in Images 4a-4c at http://www.woodstone-corp.com/cooking_naples_style_dough.htm
EDIT (6/14/16): For a Wayback Machine version of the above inoperative Woodstone link, see http://web.archive.org/web/20090215125027/http://www.woodstone-corp.com/cooking_naples_style_dough.htm