Tristan
I'll start with the good. The second shot is a good shot. You've done something I have yet to master since I don't have a tripod
The silkiness of the waterfall is nice, but not overdone.
So how could these be made better? the waterfall shot is a little dull colourwise and the foreground rocks distract from the water. I'd lighten the image a little in PP and crop a little tighter, especially the foreground rocks.
The first image is more problematic. Sunset shots grab the viewer because of things like their incredible colours or the way the sun lights the clouds or the interesting geometries of horizon elements like trees, mountains and buildings thrown into silhouette. In the image there are pieces of these present, but none screams out at you. The image would probably have been better with the sun a little lower. The blown highlights where the sun is would be gone and you'd probably have a more orange sky. There are great clouds and the sun would probably have picked them up nicely too. Getting lower to the ground and moving angle of view slightly to silhouette the trees more would also be an idea.
Once thing I do when taking sunset photos is to start early, with my EV set down by 1 to 1.5 (hence darkening the image). This gives me an idea of what things will be like as the sun gets lower. Sometimes shots like this work very well. As the sun sinks, adjust the EV back up and experiment.
Here's a suggestion, in Canberra you get lovely autumn tones. Find a location easy to get to. Rug up & take your camera. Over a week or so go there a few times and take the same sunset shot. If there are some trees nearby, think about including them in the shot before things get really dark so we can see the late afternoon sky tones as well as the colour of the leaves. As the sun sinks, eExperiment with angle of view and camera settings. Do nothing else. Comparing your results will refine your technique and give some great shots to post.
I look forward to more from you. Welcom to the forum.