You are happy with the way you are mapping, but somehow other maps always look a bit better ? But why ? It's the detail workout of the room ! Maybe your problem is that your rooms are quite static. A light, a few objects and some architecture against walls and ceilings. This is fine, but to give your room a little extra touch you could consider the following things :

Detail vs Architecture
To make a room look interresting you could choose to pack your room full of objects and prefabs. This will make rooms look nice but players might have problems moving around because of the ammount of objects blocking their way. Many objects often create higher r_speeds too. Another way is to reduce the ammount of objects and focus a bit more on your architecture. A nicely worked out pillar often is as much as an eye-catcher as a load of objects. Same is for the ceiling. with a few blocks you can make interresting architecture.

The best is to have a balanced mix of architecture and objects, this will lead to a nicely detailed map without harming the player's 3D space and the gameplay.

Lighting
Lighting can give your room the extra touch it might need. Instead of using the standard yellow light you can choose to give them different colors and brightness. White lights often give more atmosphere to your rooms. You can decrease the amount of brightness of the white light to make lights smaller or darker. This gives more feeling than one very bright light.

Another thing is to make different colors that fit in your room. Blue, red and green lights can give the player a whole new look at your maps. And instead of using just the light-texture and the light-entity you can give lights a glowing effect. This often gives more atmosphere to your room too. These technique's are worked out on the next example picture :

Dynamic
Your rooms feel static ? Then let's put some action into your room. As for an example : When you build a warehouse you`ll often have a basic room with crates and some architecture. It's fine, looks nice, but for some extra feeling we are going to put some dynamic into your warehouse. An idea is to have a few conveyors transporting around crates. These conveyors do not even have to be usable by the player, but just as some extra entertainment and feeling for the room.

People love it when things happen. You can suprise the player by letting objects fall down. Another things is : walls being blown away by explosives and grunts storming into the room. People want to interact with what you have in your room. If you have a computer in your room, than make sure something happens when players push around on the keyboard. It's not gameplay functional, but it creates a nice feeling. More things like having flickering lights, sparks on damaged objects, ect, ect, it all gives people interaction and feeling on your maps.

I hope you have picked up some new idea's to use in your map by reading this guide.