I remember when I first learned about Tikz. I sat down and read most of the manual in one sitting (this is NOT a great way to learn anything, in my opinion), and I used Tikz everywhere. I would make a powerpoint using LaTeX/beamer simply so I could make some cool animations. I am not quite so excited to use it everywhere nowadays :)

The Tikz manual is very well written, and the author, Till Tantau, includes a section on general tips for creating graphics. He rightly states that graphics should be first-class citizens of papers and presentations. He also says that you should outline and plan your graphics before you jump straight to writing Tikz code. I wish I followed that advice more a few years ago. Tikz is beautiful, but I find nothing holds a candle to planning a graphic than pencil and paper.