Well, to start with, I have to say that it's certainly a better paint job than my first 40k model.
I think my favourite part is the skin. I don't know if she did it intentionally or not, but whatever she did to paint the skin has ended up with a very nice combination of shading and lighter colours on the raised areas.
My main criticism would be the combination of colours on the head. I can't help but feel like the bright colours on the beak and quills seem out of place. I think it would work better if one of them were changed - my pick would be to make the head quills the same blue colour as the body quills, but altering the beak colour could work too.
When choosing colours, the biggest advice I could give is that planning is crucial. Before putting anything together take a while to think about how you want the model to look. It could be something simple like adapting the official scheme a company studio uses, or it could be influenced by inspiration from a TV show or history. Once you've got a clear idea of where you want to go you can then start working out how to get there with test models.
As a general rule of thumb, it's usually best to make sure a colour scheme is as cohesive as possible. To start with I'd suggest focusing on just two or three main colours for a model, a couple of secondary colours on smaller or rarer areas (like bare heads in an army that usually features models with helmets) with a few others applied sparingly as details or spot colours. You can use a lot of different colours at the same time on models, particularly if you want a motley or anarchic look to the model or army, but it's harder to pull off well. At the same time, try to keep the overall tone consistent between colours - if you want a model to look bright and crisp, only use a few darker colours, while if you want a darker and more subdued look, try to keep the bright colours to a minimum.
Here's a couple of examples to see what I mean. The first is a Firewarrior that I painted as a test model.
It's a good example of a simple, coherent colour scheme - two main colours, sandy ochre on the armour and dark brown on the undersuit, with a secondary colour in the dark metal on the gun (and some of the backpack, but you can't see it from this angle) and a couple of details picked out in red, green and gold. The end result is a concise visual with a focused look.
Another example is this converted Spellsinger from my Wood Elf army.
Again, three main colours - red hair, green cloth and white on the unicorn, with a few secondary colours (brown wood/leather, pale skin and a pale blondey yellow on the unicorn's mane and tail) and some details in spot colours. It's a little bit more complex here, as there's a couple of different variations of green and brown present, but the overall principle can still be applied.
Of course, this isn't a hard rule - painting models is after all an art, not a science, but it's a good guideline to go with when you're starting out or unsure about a colour scheme.
In terms of paint application, I'd say she's on the right track. Like I say, the skin has come out really well on this model, and while I would point out that the leather and head quills are a little flat, I'm assuming that those are still a work in progress and a trick of bad photography respectively, so I'll reserve final judgement until the model is finished.
I think that's about all I feel like I'm qualified to say at this point, but ideally it's a start.