Luke Towan's BCR broadcasting channel and his accompanying website is the go-to how-to channel for scenery as far as I am concerned. As most wargamers appreciate, model railroaders have the advantage of applying scenic techniques to static environments but of course many if not most of their skills are readily applicable to modular wargaming needs.
Luke is a fellow Aussie with over 846,000 subscribers on YouTube (yes, he's another YouTube broadcaster) and without bothering to break it down, he simply produces high-end, professionally presented product.
He has produced 80+ episodes over the past five years and the results he achieves are simply beautiful and it's a joy just to watch him design and build his terrain pieces.
From a nationalistic perspective, it's nice to have an Australian presentation because the products he uses are readily available to me. It's funny and unhelpful at times how products are not always internationally distributed or available and are released under alternative labels with divergent names and descriptions. Just try and buy Wilder oil paints outside of the USA for example and what we call MDF is by no means a universal tag.
This is a must use channel if you like to build your own terrain features and whilst it's all HO or 1/72nd scale (20mm) his techniques are all scalable and universally applicable.