woah nice landscape studies, good use of colour and nice edges especially on the trees in the second waterfall. Be careful not to use too much black in your shadows though, keep that warm versus cold in the mass lights and shadows. Also try not to search out every single detail in your work, it's better to suggest or even leave out certain details that detract from the overall impression.
Good work Dom, I see you're painting lots of shiny things and there's possibly a danger when you paint non-reflective surfaces you might suffer with the values.
So more old master studies: John Singer Sargent, Anders Zorn, Velazquez. Avoid those 18th/early to mid 19th century brown school artists for now (Velazquez is an exception though because he generally didn't use brown for shadows, and was god like with edges and tones etc)