Hi !
Did you guys ever had that problem when you are looking at hammer editor and think "I want to make a hallway. But how......".
I do every time. And that is my question.
How do you guys make your maps so visually good.
This question is adressed to everyone.
And please dont tell me "hard work" because i already know that and with hard work alone I can dig a hole, not make maps.

How do you find the flow ?
Where are the doors to professional level design and not just in source engine.
Is it a talent that you are born with ?
Please tell your story below.

Everyone fails when they're new at something. The important thing is to learn from your failures. When you make something and you aren't happy with it, try and figure out what about it makes you unhappy with it. This is the number one skill that you need to develop, and you can only develop it though - wait for it - "hard work." It takes time.

On a similar note, you should be looking critically at other people's maps when playing them. Ask yourself why the mapper put something in one place instead of another. Ask yourself if that thing would've been better off being somewhere else, too! Pay attention to everything, and be as critical as possible.

Another skill that's good to have is to make sure you're making every decision with a purpose in mind. When you're placing the puzzle elements in a chamber, what makes you decide to put the element in one position rather than another? You should be considering what positions make it easiest for the player to understand and solve the puzzle. When placing an observation room in the wall, why place it in one position rather than another? You should be considering what shadows it will cast on the wall, as well as if there's a particular area of the room that you'd like to highlight. Every single decision you make should serve some purpose, whether that's something as major as "I need to highlight this area of the map to the player because it's important that they see it" or something as minor as "it looks cool."

Lastly, remember that it's okay to quit on a project. I'm all for trying really bizarre and new things, but one of the best things you can do for yourself is learn when it's time to move on from a project. Especially when you're learning the basics, a lot of your work isn't going to turn into anything good. Sometimes it's also good to intentionally make maps that you don't plan on finishing. This is called process work, and it's similar to how artists will use sketchbooks. They spend just about as much time planning a final product as they do actually making it. For mapping, this means you should try to make a very simple version of your map that is, at the very most, playable. The in-game level editor is great for this sort of stuff! I use it all the time to plan out puzzle designs that I later transfer to Hammer, and make into proper maps.

I can only agree with everything Idolon just said.

Studying how games do things and why is a very very good way of improving. I spent a good bunch of hours last week playing Alien: Isolation, and whilst playing the game I took a whopping 638 screenshots of things that caught my eye and that help me get inspired. This ranges from interesting geometry, to lighting, models, particles etc. When the door to this room opened up I stood there for about a minute, admiring the amazing design on this room:
image be here

Let me explain why this is such a darn awesome room:
1. It's clearly some sort of lobby
2. Clearly the room is in decay and abandoned
3. To your left you can see that you're in space.
4. The way the lighting is done in the top right of the image immediately tells you that that's where you have to go.

Those are all observations you can do either subconsciously or consciously in a fraction of a second. Which is the sign of a great design. When you go look into it in a bit more detail you can admire the geometry, the textures and the lighting as well. When you look at these kinds of things and how they're achieved you can learn a lot, and that can only make you a better mapper.

Now let's dive into what Idolon described as the sketchbook approach:
I once upon a time started to work on a little corridor for a map I was working on:

I just did some rough brushwork for the arched part on the top, and just used some placeholder textures, and honestly quite terrible lighting.

The next iteration has a more smoothed out arch shape. I changed the brushwork out for a model,a nd I also made the light a lot dimmer. Making it look a bit better already.

Finally, after spending an evening in the theater I came up with the decorative things on the sides and the color palette I was going to use here. The walls are made of a somewhat pink color, but the yellowish light makes it look orange, all learned from paying attention to the wall in the theater. Because as soon as I saw that I knew that was what I was going to use for this corridor.

So what happened to this corridor? Well, it got cut.
But I learned a lot about modeling from this corridor, I learned a bit more about lighting etc.

All I can really do is echo the thoughts of Idolon and Lp. For me, the biggest thing that helped me to improve was looking at other people's maps. Often times when I was starting out, I would almost completely copy an area from a Valve map because I liked how it looked.

I zoom around the reconstructing maps, and think "Oh, this looks really nice with the squarebeams and the metal and so on", so I try to emulate that in my maps. Or, alternatively, avoid things that I don't like the look of. Recently I used a Valve map as an example for an airlock hallway, but I didn't like the way it looked (too bland) when I tried to recreate it in mine. So I spiced it up by putting a catwalk over some pipes instead of just 512 units of a factory floor texture.

I'm not saying you should just blatantly copy, of course, but it really helps to see how other people do things, and then use that as the basis for your own work. This works really well for puzzles, too.
Eventually you just get the hang of it, and don't need to check what other people do. And eventually people will start using YOUR maps for inspiration!

I have found that, by carefully observing your world, you can often come up with things that you might not have thought of before. For example, I was reading a guide for optimizing levels in hammer and it inspired me to make a level.

Many of the levels I have released "into the wild" were inspired by the world around me.

Thanks you guys for answers.
With observing the world, from now on I have a great excuse for making 2 buildings that have completely separate and different styles, yet they are 2 meters away from each other.
I live in Cracow, go and have a street view of it.

If you know the basics of hammer, and you already know your map's layout, but dont know how to detail it, the first step for beginners is to make the map and hallway in the PTI editor and then start editing/modifying that.
First to retexture it
Then you can add details, change the walls, make some hole (if you want destroyed/decayed style).
Then add some model, squarebeam
Then add some vegetation. For these, you should pick and remember your favorite models, so you dont need to browse thru all the models in the modelbrowser to find certain elements
Then add/tweak lighting
Then if you are not happy with the detailing or want more, add extra brushwork, add extra holes, broken parts, some visible bts area behind the holes, more vegetation, until it feels right (lots recompiling and checking ingame)
If its a clean style, then no vegetation, but more bts light pro and robotic arms, maybe some rope etc...
and at the end, tweak the lighting even more, and then optimize the area (converting some brush to func_detail, but thats the last step it not affects the visibility
Choosing the right textures also a big plus. PLus keeping/applying the same same stile and same level of detail to the rest of the map.

Later when you get used to mapping, you can skip some step, Can skip PTI editor, you can even start with "detailing", not just a simple hallway or testroom, and its enough to add lights at the end.
But first make sure that the puzle elements are working, because its harder to modify a detailed map, to rearrange puzzles or put things elsewhere and thus changing the layout.
Check maps that you liked to play, "steal" some desing and style ideas or create your own style.