What are Slic3r settings and how can you find out if they are right?

First of all what is Slic3r?
Slic3r is a free software that converts a digital 3D model (in STL format) into printing instructions for your 3D printer (in G-Code).
Why are settings important?
Settings are included in the 3D print Gcode and defines many of its parameters such as speeds, layer height or support materials. Silkworm includes these settings within its final G-Code.
Is there any resources out there on Settings?
Here are some blogposts which were really useful for us (we use RepRap Prusa Mendels):
How low can you go: http://richrap.blogspot.co.uk/2012/01/slic3r-is-nicer-part-3-how-low-can-you.html
Slic3r Documentation: https://github.com/alexrj/Slic3r/wiki/Documentation
Examples: http://forums.reprap.org/read.php?262,107168
Tips: http://www.lpfrg.com/faqs/4-2-adjusting-slic3r-settings/
Notes on tuning a slic3r profile: http://www.buildlog.net/forum/viewtopic.php?t=1185
On Layer Height: http://blog.reprap.org/2011/12/001-layer-height-on-prusa-mendel.html
Setting the flow rate: http://solidoodletips.wordpress.com/2012/08/16/setting-the-flow-rate/
Some makers share their settings on their blog, have a look at the following ones:
http://brazenartifice.wordpress.com/my-slic3r-config-file/
http://the3dprinter.blogspot.co.uk/2012/03/slic3r-settings.html
How can I check my G-code:
You can use the Silkworm Viewer (post on this soon).
You can also use the following online G-code viewers:
http://jherrm.github.com/gcode-viewer/
We also share our Settings:
Download Arthur’s Quality 3D Print Settings.
Important notes:
- Fill density: from 0 to 1 (0 is less density and 1 is higher). A higher fill density will make your product stronger.
- Top/Bottom fill pattern: Make sure to have a concentric Top and Bottom pattern, otherwise the cross-hatch will be visible on both sides (see image below).
- Perimeter: Don’t forget to have at least 1 Perimeter otherwise the infill cross-hatch will be visible on the edge (see image below)

- Refraction Speed: This is the speed at which your filament retracts when it reached the end of a path. When your edges are not clean (image below), you refraction speed is probably too low.

- Enable cooling: Plastic likes to cool down a little before the next layer is deposited. Slic3r has provisions for cooling built-in, and they are in the “cooling” tab. The first thing to do is check the “enable” box (even if you don’t have a fan.