I added two new tips to the tutorial. Feel free to send me your favorite Inkscape tips for inclusion - preferably something non-obvious, useful, and not documented elsewhere.
Clipping or masking a bitmap
By default, an imported bitmap (e.g. a photo) is an <image> element which is not editable by a Node tool. To work around this, convert the image into a rectangle with pattern fill by Alt+I ("Tile"). Now this object can be converted to path, node-edited, intersected with other shapes etc. In Preferences (Misc tab), you can set the option of always importing bitmaps as tiles.
Open dialog as an object palette
If you have a number of small SVG files whose contents you often reuse in other documents, you can conveniently use the Open dialog as a palette. Add the directory with your SVG sources into the bookmarks list so you can open it quickly. Then browse that directory looking at the previews. Once you found the file you need, simply drag it to the canvas and it will be imported into your current document.