On Windows XP, I really enjoy using TeXworks 0.2.3 (r0.466), which provides with an editor window and a document preview window. Clicking in the document preview locates the edit mark at that TeX source corresponding to the clicked location.
I find this to be convenient for documents containing diagrams and many pages, when I have been used to working in an environment like Word.
TeXworks is open source and the fruit of the TeX Users Groups.
I've enjoyed learning LaTeX from A Guide to LaTeX 2e, by Helmut Kopka and Patrick W. Daly, pictured below:

When I need to write a new document, I usually look at the TeX source for similar documents. For example, when I first needed a business letter, I started from an example business letter. Eventually, I have developed a TeX source which I include as the preamble of a business letter. This source applies my choices of style and is stored in a directory as its own file. Thus, if I want to change something about my business letter style, I can do so and change all of my future business letters when I compile them or when I recompile the old letters.
Similarly, when I create diagrams and figures, I create them in a file of their own. I then include the diagrams from their source file.
This is very different from Word, where the diagram or figure is essentially part of the text document. In particular, I am able to have more than one document include the same figure. For example, my article can contain a figure which is also shown on my poster. Because the diagram is rendered from the same source file in both cases, a change made to the diagram is immediately available in both documents.
With very long documents, it becomes useful to "factor" the document into chapters incorporated into the document via include. Then, the include-only command may be used during revisions to avoid recompiling any unchanged chapters.