[Tristan Lall]

Also, with regard to structuring the models themselves, it's often convenient to choose features that logically approximate the machining processes that you'll use. Use hole features for drilled and screwed holes (instead of cuts). Use cuts for cuts. Use subtractive features when machining from stock.

This will help guide you to design parts for manufacturability. However, there are many exceptions to this: it's just a suggestion, not a rule.

One other thing to keep in mind—and this one is pretty much a rule, not a suggestion: fully constrain your geometry. SolidWorks allows you freedom in leaving things unconstrained in your sketches. But this makes the sketcher a lot less powerful for use as a mockup, because you can't reliably adjust the sketch without other things being affected (sometimes subtly). You don't have to fully constrain it to start with, if you don't want to, but at some point it usually makes sense to freeze things.