I think we could use this thread to discuss some mapping tips, tricks and common errors are not usually talked about in tutorials, but are still important. Most of these things apply to both HL and Source, and any other game level editor for that matter.
It'd be nice if people post their ideas and things they have trouble with while mapping (I'm not talking about a certain problem with a certain map)
You dont need to tell all your tricks. Some mappers are really secretive about how they work. But if you want to share anything, people will appreciate it.
Ok. Most of you probably know this, but other people (even people in the game industry like F.E.A.R's level designers) are still making this mistake.
It's not hard to see that the stairs on the left look really bad compared to the ones on the right. That's because they were made with several copy-paste commands and no retexturing at all. With a longer staircase and other textures, this effect can be horrible-looking.
Solving this could be as easy as selecting the odd numbered steps and giving them a scale of -1.00 in the X axis.