Land Patterns and Component Spacing
One of the biggest causes of challenges with assembly these days seems to be component spacing, as I wrote about here.
We reference IPC spacing guidelines from time to time. Like, we'll say: "use IPC spacing guidelines" and stuff. That's all fine and good - unless you don't know where to go to find the IPC component spacing guidelines.
If you can't figure it out from there, a 20 mil courtyard is generally a pretty good rule of thumb.