Consider the following situation: you are developing a RTS, with different races opposing each other, with different kinds of abilities (e.g. Starcraft). How should I go about in balancing the damage, speed, cool down times etc. of the respective troops/units? Are there any good resources on that or sort of test-beds?
Balancing is really an art form, but it comes down to balancing rock vs paper vs scissors, meaning that in-general rock should beat scissors, scissors should beat paper, and paper should beat rock.
How easily rock defeats paper can be dependent upon other advantages and disadvantages of buying a rock, such as how it fares against a paperclip or a tree, how far you can throw rock, and how much it cost you to get that rock.
That being said, balancing in-general is very specific to the game, and there is rarely a place where you can plug in values, and be given a straight answer (such as 'overpowered'). There are some factors that can play a very important role, though. In many games, Damage Per Second (DPS) can provide you with almost everything you need to know about how powerful a unit is.
Using values like DPS, it's possible to create a formula that will give you an idea of how powerful a unit is. For example, a unit's 'effectiveness, could be the value that combines a unit's 'Power', 'Utility', and 'Defense'. However, telling you how to get these values is (as I mentioned before), very specific to the game you are making.