uh this is my first critique so sorry if its not good:
First of all i need to say i like the girl shes really cute~ Trough you could put more details in the madders shes sitting on but on the other hand i'm not sure if its a madders. It cool when it has a little old-time feeling in it but then there's the computer that is kind of from our time and then the boards that seem from the future that is really cool.
All in all i really like this and the feeling it gives.
Overall, I really like what's going on in this picture. I'm not sure what's she's doing with the fan though. Is she using it like a mouse, or is it just a fan? Whatever she's sitting on, the clothe/cushion part looks really stiff. It looks like a box with fabric stretched taut over it. Unless that's what you're going for you should round out the corners a bit and add darker crease lines under her rear. I always appreciate the perspective points you use in your art though and this piece has a very complete feeling to it. This is actually the first time I wrote a critique now that I think of it. I hope this helps.