Use paragraph styles as much as possible, because this is a very convenient mechanism to control paragraph layout and it furthermore enhances ITP performance when producing large result documents.
You should be aware that the result document you produce has to be a valid Microsoft Word document. This means among others that the document that you produce always has to end with a paragraph ending. Realize this in particular if you call the function put_in_document or add_to_output.
Turn off Store random number to improve merge accuracy.The option Store random number to improve merge accuracy on the Security tab of the options dialog of the Microsoft Word XP Tools menu should be unchecked. This option can cause the model creation process to fail. ITP will issue a warning if a Microsoft Word XP model is translated with the option checked. This warning will be shown in an error document. Note that this warning in itself is not enough for an error document to be displayed. Also note that when this warning is issued it is likely to be issued several times for the same document, once every time ITP encounters it.

Do not use revision marking on model documents. Revision marking a model document may result in models that produce unexpected lay out in result documents. The problem is that a revision marked model document will compile into a model without a problem. It is only when such a model is run and the result document is examined that errors can be found. Since there is no elegant way of filtering for revision marking we strongly advice you to not revision mark model documents.