For the sake of moving this argument along I'll put my cards on the table and say that the price i've been
looking to get paid is roughly £150 p/min (roughly $300 p/min) - i always retain rights but the music is also pretty much always exclusive for that project. Whether I've been paid exactly that every time is another story but that's probably the figure I would throw into the ring when discussing prices. That's my costing based on my own valuation of my music, my valuation of my reputation, my expectation of what developers of the caliber i'd expect to mostly be working with can afford, how much I think is a fair rate in terms of the time I will put in etc. Hopefully, this price will increase with time and everything but you really have to take each project as it comes - see what their budget is and see if that's something you can work with, if not keep on searching - if after a while, no one can match your price, perhaps you ought to re-evaluate.
From the moment I started I was working for free on various small things. I had the occasional pay and that encouraged me to seek out more things that were paid - these would only be something like $50 per track (not minute) or even less. And then as more people come to you with bigger prospects out of the contacts you have made doing these small things, you can charge more. Unfortunately, your skill isn't immediately worth something unless you're particularly lucky in finding or knowing people that will take a chance on you and/or recognise your ability right away. However, to be completely blunt, I feel you still have work to do that if I were you, I wouldn't expect to be paid $300 p/minute - just being honest because I think that's what you want.
The problem I PERSONALLY have with your music is that you seem to be thinking "what does video game music sound like? OK, I'LL WRITE LIKE THAT!" It's imitating a very broad and generic style that everyone does to begin with but the music ends up boring and predictable. I went through the same kind of process of thinking "what kind of imaginary video game music can I write" and at the beginning, the results you come up with (if you are dictated by the idea of what you should be writing) is really uninspiring stuff. Imitating is fine and good and everyone does it, to a certain extent - imitation of something very specific that you love and then moving on from that is a good method but imitation of the broad idea of this generic sound is what bores me in particular.
If that is what you are talking about then that is good for me to think about, but isn't it a highly subjective matter? It doesn't seem especially relevant to video game music. It sounds more like advice for pop music. Verse-chorus-bridge structure isn't so applicable in classical, or film, or game, or ethnic or a lot of electronic music. Whatever it is you guys are talking about it must be something that you care about more than I do. The question then is, am I abnormal?
I get the impression that you write in this way because you say "It doesn't seem especially relevant to video game music." You see video game music as an exception to the rules - like some sectioned off thing that doesn't have to compete with other kinds of music! YES, i will not deny that video game music has a function and there are some expectations it may have to meet BUT this is no excuse to start to think "this game music only sounds like this", "this is the kind of music I'm expected to write". That's exactly what your music is sounding like to me. I would be surprised if you wrote some of this stuff without the purpose of it being for a video game. Don't take this as gospel since it's a very personal feeling I have but I do believe there's a big problem with people writing the kind of music they're expected to write - it's not a specific genre but more a method - I can't really explain but it seems to be the kind of music that people write at the start of their career before they've found their own voice and the kind of music they really really want to write. I'm not saying everyone should write the most unexpected thing that doesn't fit in with the game at all BUT people write better and more enjoyable music when they're not obsessing with the thought "this is how video game music sounds".
Again, I've been totally harsh but I don't want you to take it as a negative thing. I've just been as honest and blunt as I could be about my own experiences and my perception of your current situation.
also, ideas about charging people based on "how many instruments are you using" - some people say "oh, it's just a chiptune, that's cheap" or "woah, A REAL VIRTUAL INSTRUMENT ORCHESTRAL SCORE - BIG BUCKS FOR THAT!" It's total BS. I wouldn't ever valuate my stuff based on that. I personally feel like the style or instruments i'm using is my responsibility - i'm going to give my all to everything so there's no need to change a price for that - chiptunes take a long time if you do them well, orchestral stuff takes forever if you're not very experiences at it.
I hope you don't take this as an attack. I haven't given much specific information about how to improve your individual tracks more general advice but others have given good advice and hopefully you'll get more in the harsh crit thread.
TL;DR VGM is sick - don't make generic shit. money is a tricky subject - keep at it!