[amelius]

I always wonder: how do you find the parts you need to build such things, and how do you make sure they fit together without spending enormous amounts of time in various online parts shops?

[veli_joza]

In my experience, either you get exposed to various parts at your workplace/college, or you stand on shoulders of similar projects.

[Neliquat]

3 ways.

1. Already know enough to glance at some spec sheets and build the rest in your head. Aka, lots of experince.

2. Execute a known good build configuration.

3. Combo of the 1st and 2nd points to suit your ability. Ask people with more knowledge for guidance. Maybe rebuild it once or twice.

[SauliusLukse]

Experience comes with practice :)