Disclosure: I'm the maker of Artluni, so this is a self-share.

A composition tip I keep coming back to when critiquing landscapes: avoid putting the horizon dead centre unless you're deliberately going for symmetry. Decide whether the sky or the foreground is the subject and give it roughly two thirds of the frame. Crop a few different ways before posting and ask what the eye lands on first.

If you'd like feedback on your own shots, Artluni is something I built for sharing and critiquing photos. The launch code FOUNDING50 is in the link. No pressure at all. If you do try it, an honest review on Google Play or the web version would help me a lot, including the bad bits.