Whilst the Vox instructions provide a good guide on how the buildings work, and what they do - there’s a shortage on details as to what the best guide for actual building placement is.

I hope to give you a good starting point for Resource building placement. The general information on where and how to place buildings is covered in the Vox instructions.

The Basics - Building Classes

There are two classes of buildings -  Military, and Resource Gathering.

Military buildings are rather simple - they can be built, for the most part - almost anywhere that is either within your sphere of influence, or neutral (unclaimed) territory.  The placement of these should be closer to enemies, or likely attack vectors.  Because they do not impact upon the production of a tile, you do not have to consider their placement quite as much.

Stockades should be used to provide automated defense throughout your territory, and as a first line of defense.  

Resource Gathering buildings, as the name suggests - gather resources which you can use to fund your empire.  This is what the main part of this guide will cover.

Selecting a location for your Resource Gathering building.

Location, Location, Location. Yes, Location is everything in this game, if you want to get the optimum resource gathering capabilities from your land.

All resource buildings have a Production Area. For first level buildings, this is simply the tile they sit on. It is when you start upgrading buildings that your positioning really matters. 

Here’s an example of inefficient building placement:

This is a typical beginner mistake - Sure, at first this provides a small boost in efficiency, however the majority of these buildings cannot be upgraded. In addition, those that can be upgraded will be less efficient due to a different, or mixed resource availability on some of the tiles.

Here’s an example of better unit placement: 

All buildings have a two-tile gap between each other, which means there is no impediment to upgrading to Level 3.

There are some problems with this placement, however. 
For instance - Mines can only produce metal on Rocky Hills (preferred), or Scrub Hills (only partial efficiency). 

All of these mines have been placed on the edge of the Rocky Hills, and thus will only have partial efficiency when upgraded.  This is because the production area will expand onto Plains, which has only Food production capability.

This is an example of significantly more efficient building placement. All buildings have atleast a 1 tile gap around them, and have 2 tiles between each building meaning all can be upgraded to Level 3.

Most buildings have full efficiency, only the mine has partial (due to being next to a Lone Mountain).

Of course, some times it is not possible to get nine tiles in a square that are the same resource type, or you’re forced to use Scrub Hills. This is where Outposts come in handy - since, unlike Farmsteads, Mining Pits, and Logging Huts can produce resources of any available type.

Outposts are especially handy when you have access to Mountains and Blights. Once upgraded to Settlements, Towns or Cities - they can produce Relics and/or Gold very quickly. 

Handy Tip: You can build directly on top of blights for an additional boost in your relic production rate.

Gold Ponds are the best source for gold - be sure to place a few workers on it to increase the gold production.

Small Islands are also excellent locations for upgraded Outposts, as all water has a certain percentage of Gold in it. 
Update: As Christina points out - these are also excellent locations to build Stockades. These give an additional defensive capability, they also help to control more territory (which means a higher score).

Just watch out for the Velociraptors, as they are known to hang around small deserted islands such as this.

I hope this little guide has been useful. Feedback/Comments welcome.