Improved Skills is a simple to use mod, that allows you to define custom multipliers for each skill change the pace at which you progress them. The way this works is by simply playing the game. You can change all settings at any point via the default settings menu. Just click on the "Mods" button in the top right corner of the settings menu. There you can enable/disable the mod in general, choose whether you want this to work on servers and set the multipliers for each skill.

This is a very simple and easy to use mod. All you need to do is install it and play.