Hey there!

So firstly, your terrain. I really like the dynamics and the atmosphere you've created with the pathway and the cliffs surrounding it. I like the palette you've used - an all around lovely terrain plot :3
If I said one thing, it'd be mix more stonetextured blocks in with the stone (stonebrick, andesite etc) to give the stone parts of the mountains more details. As well, mix some dirt in with the mountain, so its not all stone with a little bit of grass on top.

Secondly, organics. I like the shape of the tree, it looks really nice. But I think making it out of clay was a mistake. With a plot like this, natural blocks (logs, leaves, maybe some coloured glass) would look so much nicer. Clay is more for fantasy plots, which this doesn't give any hints to.

Lastly, your structure. I know you said you weren't good at structure, but everyone can learn!
This structure does need some work however.
There are two main aspects to a structure that you absolutely HAVE to consider when building – depth and detail.
Depth is the use of layers. Simple depth is created through the use of a frame. A frame can be made simply, or it can be more creative.
Simple frame:  https://imgur.com/ONsoRxh
More complex frame: https://imgur.com/20eZjP8
Those are just two examples, with no palette, to demonstrate the difference that can make. You can use that on all four walls and make a small house, or you can make a larger structure with the more complex frame in the image.
However, these are both very basic still, we want you to be as creative as you can be!

Detailing is the use of slabs/stairs/cobblestone walls/fences etc to show details and a pattern or interesting aspect to a build. Small detailing like fences/trapdoors tend to be used on smaller structures, like houses or towers. And slabs/stairs tend to be used on larger structures, if not full blocks. Detailing can be tricky, as you don’t want to over detail. You also want to bring the detail into the depth and create multiple layers of it, instead of just one layer of detail in front of a flat wall. Again, I advise you to fly around spawn, have a look at some of the plots in the black carpets around the very edge and see the type of standard.
I want to stress this now that you don’t have to build that well in order to rank. Most of those builds around spawn are exceptional and we do not expect this of every single person who comes on here.

So your structure that you’ve made doesn’t show much depth or detail. It also is made out of really random blocks, which doesn't show much thought was put into the palette.

You’ll need a roof, however. Roofs can also be tricky, but there are many styles of roofs.
Medieval/Elven style roof: https://imgur.com/a/Lr9Ab#0
Rounded roof: https://imgur.com/WgvhAUP
Oriental Style Roof: https://imgur.com/vo2A2Bu
Pointed Tower Roof: https://imgur.com/csiGTVH
Hopefully those roof styles give you some idea of a route you’d want to take. They are very different styles of roofs for very different styles of builds, so I hope you find the right one. My only advice for a roof would be not to use all stairs/slabs. I think you need to use full blocks, with maybe some stairs of slabs for detailing. I think it’s always nice to have an overhang too, so the roof doesn’t match up with the wall. And lastly, make sure your roof is a different block to the walls, so then there is a definite difference!

Good luck!
Sorry for the length, but I hope this helps you build a great structure!
- Dutty :3