This was my set of comments the last time a similar topic came up. Personally, I always try to go into a map with a focus in mind - trying to just randomly toss stuff down and make something stick frequently doesn’t work for me. Even if it’s a rough, “placeholder” set of ideas for features on a map, I try to at least have something lined up, because it makes a map feel more well constructed and a tighter experience in flow, IMO.
It obviously helps to have the map also reflect what’s going on in the story as well - if it’s a climactic moment, then having a map fit that feel should be an objective in mind in its creation too. In terms of resources on how to create maps easier, like I said in the comments above, doing a little preliminary sketch to get down an idea and get some rough dimensions will help with the planning. Alternatively, you can always load up Yeti’s FEMapCreator and just have it generate random maps until you get some features that call out to you, locking them in and then continuing to generate until you get kind of a “base” that you could use as a template to construct something entirely from the ground up.
I also really like to do maps “as practice”, adapting images or chapters from other FE titles and converting them to GBA representations (using different tilesets, changing features and adding gameplay mechanics - see my recreations of Chapter 6 from FE9 and Chapter 24x from FE5 in my thread) - it’s a nice challenge to replicate the maps and features and think of ways to change the gameplay as you’re making changes to the elements of those maps and designs.
In terms of enemy placement, I think having a good plan in mind for the flow of a chapter would also assist with that, as you’ll have an idea of “bosses here, enemies in these places to act as an impediment for the player, etc.”. Trying to just randomly place enemies probably will make the flow not as smooth as having something more tailored in mind.