The basic rules are relatively simple: It's the ability to move and convert different types of energy at the cost of a little wastage- for instance using the wind to move objects around
Ari, what's the wastage in your system? Is it that some of the energy is permanently lost? I.e. you're using the wind to move things around, but it's not 100% efficient because you can't concentrate the wind on just the object? Or is it something more personal, such as your Idamancer's personal costs (fatigue, blood loss, memories disappear, somesuch)?
Part of the wastage is in the magic used to create Ida, (which I cannot talk about for spoiler reasons, but suffice to say there was a significant up-front cost) and part of it is in the fact that an Idamancer isn't 100% efficient. Unless she uses some sort of magical turbo-charging stunt, of course, which is known to happen in fantasy now and again.
So yeah, you get a weaker wind or tide when you mess around with kinetic energy. If you were to dance a flame across multiple candles, you'd need to give it time to build back up or you'd eventually kill the flame. I have a character who is adept at moving flames, and uses them as punishment.
Innate strength in Ida is about transmission efficiency, which improves to some degree with practice. The best Idamancers in Dreamspace achieve about 90% efficiency. Skill at Ida is the ability to move a larger amount of energy at once while maintaining efficiency, to convert energy types, and to move energy across multiple channels at once. There's also some neat pseudo-chemical themes to the magic, as they think of energy in terms of "elements". ie. chemical potential is called "earth energy", gravitational potential "air", kinetic "water"*, heat "fire", electricity "lightning", and magnetism "metal". Idamancers on Temeros haven't discovered nuclear energy just yet, but I imagine they would call it ambient energy.
*Which leads to some strange talk about wind being water energy moving through the ether and the entanglement of air and water, so that wind contains water energy and rain contains air energy. Pseudoscience is fun.