Techniques I used to create some of the elements:
For the heating I started with a torus I stretched out and extruded at the top side the “connectors”, then I added an array in the Y axes and applied it so it creates 1 mesh. For the input pipe and the control knob I extruded the leftover connectors to model. To get them round, the only thing left to do, was to use the subdivision surface modifier.
The plant leaves come from 1 plane I subdivided and deformed, inspired by this tutorial on Youtube.