Tips and tricks in room creation

The idea came from EnkindleThis, to help out others with nifty things that we do when making a room. There were useful tips in comments from a vast variety of posts. This thread will help to condense them all into one.

Now you'll be able to get inspiration from event threads, and the tools to make an idea into reality :)

Here's a list of tricks to help align objects in the room, rotating many things at once, and building up a beam without that last block always dropping to the ground.

And as an added bonus, my guide to making waterfalls.

Please add in any other tips that you think will be useful for others.