Map making tips

I understand you know about tutorials, but TopHATTwaffle has certain videos that explain EVERYTHING you need to know on that topic. An example would be his optimization video, if you watch that, you'll know everything about optimization.

If you make a block, click on it, do edit and press "Make hollow" this will make a room with 4 walls, a roof and a ceiling in seconds, it's a very helpful feature and I'm not sure if you knew about it already.