Tipsntricks

Interface

Left-clicking on the [E] (Envelope) buttons while pressing shift will remove the envelope. Likewise, pressing shift-left-click on a [T] (Texture) button will remove all texture in that channel.
Right-click and drag on a colour widget will increase and decrease the brightness of the colour without having to adjust each component individually.
You can save a scene called default.lws into [your content directory]/scenes/, and it will load automatically every time you start Layout. You can even set Layout to load this scene automatically when you clear the current scene.

Middle-click will add elements to the selection in Modeler without needing to use the Shift key.
Get the shareware AllSnap utility that snaps windows to each other to speed up arranging your Modeler windows.
The nudge shortcut in Modeler: alt-arrow nudges selected items by the amount you entered in the grid snap value (in display options)
Getting yourself a Logitech MX Laser mouse (for example) will give you loads of buttons. Using uberOptions means that you can arrange them as options in Modeler. For instance I have:

Monte Carlo and Final Gather Radiosity will automatically calculate caustics from luminous geometry.
Right-click on the values next to the colour widget to change from RGB to HLS mode and back. Left click and drag on the individual values to change them.
There's a calculator built into every numeric entryfield. Use /,*,-,+ to divide, multiply, subtract and add values
Not only do the numerics allow for calculation, but you can mix units too. So you may enter 1m + 10" - 3ft + 6cm