Depends on your aptitude. Thor's a prodigy, I'm good, plenty of people can work for years and not be much better where they started percentile-wise.
...Well, I can't say it's not ingenious but it still sounds like a terrible idea. If you go sufficiently stir-crazy to do something like that and you mysteriously turn up in one of the newcomers' camps rather than the Enemy's I'm going to be teaching them, though.
If you have any songs besides the crop one and the happy-and-energized one I could potentially use those, if not necessarily for combat applications.
I don't really object to making food taste better, actually, but I'm not sure there's that much demand for it. Maybe Brithombar would gain a new appreciation for lobsters?
My spells aren't direct damage types either. I wanted things I could use in the conditions I was in, like you. I've got a song that sets things on fire but somehow I don't think defeating Thauron will involve something as straightforward as setting him on fire. Or shooting frost beams at him, if I ever figure that out, I discovered recently I'm not the species I thought I was but I can't seem to make use of the information productively.
Well, normally, yes! However, when I fought the Balrog it seemed to somehow wear through what seems to have been powerful non-sorcery magic causing me to look like an Asgardian when actually I am a frost giant with stunted growth or something! My hypothesis is that Odin kidnapped me from Jötunheim as a baby intending to raise me with Asgardian values, conquer the frost giants once and for all, and install me as a puppet ruler, isn't that lovely?
I won't turn one down but I am actually okay about this one, it won't be relevant to my life except possibly in a nifty ice powers way until I figure out how to go home, find out if my sister will hate me, find out if my father knew about it, etcetera etcetera.
Thor would never have considered it remotely possible that she could have a sister who was a frost giant. The species aren't related in any way. She might decide that I am adopted, therefore not her sister, therefore just a frost giant, possibly 'a frost giant pretending to be her sister'.
...The mental image has some appeal but I am not sure it will work very well for a number of practical reasons, starting with "she's significantly stronger than I am" and proceeding all the way through "it is extremely difficult to cause sense to enter Thor by talking or any other means".
I'm not sure yet how she's adjusted to the magic revelation. She didn't hate me but wasn't fully informed about the extent of it and hadn't quite decided how to come fully to terms with even what she did know. Certainly she'd consider it an underhanded tactic. And yes, I would, do you even have a sense-putting song?