You can quickly move all of the inputs/outputs from one node to another by using Shift + LMB Drag to another node.
On a node that takes multiple inputs, such as the Blend node, you can swap the position of the inputs by pressing "X".
By pressing "backspace" on a node you will delete the node while keeping the connections.
Use Alt + Shift to add a reroute node for a particular line to clean-up the graph some.
You can round corners by adding a blur to the shape and then adding a histogram scan after the blur to regain hard edges. The blur amount will control the rounding.
Use a Directional Warp to offset and breakup a pattern or output. Then use a blend node to finalize the mask.
Input: The thing you want to warp.
Intensity Input: The thing you want to warp by. In the case of an offset, this is the pattern you would use for offsetting the input.