I prefer the look of wood personally, so when planning a new tank, I go to a store and see what wood pieces they have, same applies to stone. If you find a great piece that you love, it often helps to build the scape from that.
Like this one from Tropica as an example:
So they either bought one wood piece that looked like that, or more likely, attached a few pieces together to make this shape. The wood and stones are the 'skeleton' of the scape, and they built the plant plans around this skeleton, make sense?
They've used a lot of easy to grow, low maintenance rhizome plants that can be attached to the wood and stone, rather than planted. I see anubius, buces and bolbitis (I have bolbitis too, love it) so while this tank took some planning, the plants don't grow fast and need frequent trimming or anything, and the cave shape and dense planting suits the ram or apisto species you can see in the photo.
In one scape I did, not my favourite of mine, but it has the most progress photos to help me explain.
I started with this wood piece I'd found, because I had plecos and cories that I knew would love the wooden cave to hide in and around. So I saw that piece as essential, and played around with other hardscape pieces to try to build a scape that would be designed mainly to suit the plecos and school of corydoras I planned to put in this tank. Cories need soft sand, so that was an easy choice to make too.
Since I had dark sand and a cave like piece of bogwood as essential to the scape, and cories like some open space to feed and potter about, I used this Tropica layout as inspiration for my own, wanting to do something with a similar mood, which I think of as "gloomy sunken underwater forest":
The hardscape and planting provide plenty of hiding space, but also left some open room for large cories to explore, feed and play.
I tried so many arrangements using different pieces! It's worth taking photos of the different arrangements you try, so you can look at them more objectively, and re-create a previous arrangment if you find you preferred a previous attempt, but have forgotten how you did it! Photos mean you can see how you had it before and recreate it.
I actually liked this look... but it's a LOT of wood, and I'm a plant nut, so I knew I'd end up removing a lot of pieces to make room for more plants. But I could just have easily kept this arangement, and stuck with slow growing, rhizome having plants like the buce/anubius/java ferns/mosses etc. But since I like a variety of plants, for it to grow a bit wild, and some fast growing plants too, I didn't go with this one below:
Next two photos, you need to decide if you want a central arrangement, or to the left or right, and what you decide to do might depend on what hardscape pieces you find and like!
Once you have an arrangement of the hardscape you like, then you can look at what plants would suit it, and suit what you want. Whether you want something easy that doesn't require weekly trimming, or a mix of both, or high tech with CO2 and delicate, deeply coloured plants!
I had some plants from my other tanks, but bought a lot too. In the next photo you'll see most of the plants are still in their pots, because I was arranging them without planting or attaching them yet, to check I liked how it would look:
After I'd planted it up and plants like the amazon frogbit on the surface were growing in:
In the end I didn't end up keeping this scape for very long because I decided I wanted a much longer and bigger tank, upgrading them from this 36g to a 63g with a bigger footprint. But the plecos and cories did and still do love that main wooden cave piece that I built this tank around, so that piece is going to be central in the 63g too!
I'd recommend having a floating plant - all fish feel safer with some overhead cover like that, and they're good for water quality. NOT duckweed though. That stuff is evil. But any other floating plant is easy to maintain and great for water quality too.
You can also mix real and fake! Some of those tanks with themes and fake decor can be some of the most fun and beautiful, and ignore anyone who gets snobby about only having real decor. Real plants are definitely beneficial for sure, but there's no law against mixing in some fake ones for a pop of brighter colour, or having a lord of the rings theme tank with a hobbit hole, real plants and some fake decor for fun! I love my real wood, stone and live plants, but I still fully intend to make some themed tanks that include some fake decor in the future. I have some decor in the cupboard for that project! As long as the fake stuff is tank safe.
From the Tropica Inspirations page:
Another easy scape idea that might suit your current tank! Low maintenance and low tech plants that don't require huge maintenance, I'd move your two current plants more towards the back, as background plants, then shorter plants in the foreground.
This one has more difficult, advanced plants that require CO2, but it's easy to just mimic the style of a layout you like, but adapt it how you like. It wouldn't be too hard to create a lower maintenance, easier version of the scape with less demanding plants:
Hope this is making sense and isn't bombarding you with too much stuff!