Designing
I use Studio 2.0 to create models virtually. This gives me the freedom to use any parts I want, even if they're not physically in my collection.
I'll spend many days working on a design, tweaking and adding or removing features until I'm happy with the result.
Once complete, I can order the parts needed online. I can also create an instruction manual to reproduce the virtual model in real life.
An excellent Studio 2.0 tutotrial and some advanced setting examples are given by my friend WingYew here.