This research I gathered from http://writers.stackexchange.com/questions/1644/what-are-common-attributes-of-the-steampunk-genre, generalizes steampunk as a romantic sub genre of sci-fi and fantasy. It states how around the era of steampunk people saw "nothing wrong with imposing their civilisation on others" and that they were "confident" and their "optimism was high". They later use "Howl's Moving Castle" as an example for steampunk with "straight fantasy".

With the influence from my previous research I decided to look into Howl's Moving Castle's take on the steam punk theme.

This image shows other vehicles based from the past era which steam punk is based in. You see a lot of steam throughout the atmosphere which is coming from steam powered vehicles, also linking to the theme.

The model of Howl's "Moving Castle"; It includes pipes, metal scraps, is steam powered and generally based the past era, perhaps 18/1900s.