Make sure to put heat sinks on parts that can overheat so they cool down faster!
If heat sinks aren't your thing, then there's radiators, which are better at cooling than heat sinks.
Just be mindful that they heat things in front of them.
I forgot to mention that parts can cause other parts to increase the rate at which other parts overheat.
However you can use insulation to reduce how much parts overheat each other, however, be aware that insulation is a very weak part and can be set on fire, though it burns slowly (crew also can't access insulation, so they can't put out any fires on insulation).
