It's usual for the GM to post what's happening around you in this sort of RPG, so I'd advise avoiding narrating the actions of other characters, and preferably avoid narrating the results of your own actions. From experience, it can get bewildering very, very quickly as a GM if bits you've planned about the world keep suddenly changing on the fly; it also kind of defeats the point of having a stat system if we narrate results of actions.
So things that are good:
"I decide to have a go and swing my axe at the big oak door."Whereas avoid:
"I swing my axe at the big oak door, and it crumbles into dust" -> the GM should be making a roll for this"I swing my axe at the big oak door - but then notice it's actually made of beech and has a pickable lock" -> the GM provides that sort of information preferably"I swing my axe at the big oak door, and a random stranger then turns up and gives me pixie dust" -> Now you're just being silly 
To take an example from the actual RPG so far, Tom's first post (sorry Tom, yours was just early on in the thread):
I bounce around on the cart as it bucks and sways along the rutted dirt road. As we start to climb the hill I look down at the grey face of my prisoner, his whole body wracked with coughs and pale with sweat. 'He's probably not going to last long,' I think to myself, now turning back to face the village below us. An ants nest of villagers all streaming in one direction, towards the big stone building with a pointy bit out the top. 'That looks a whole lot more interesting than just chopping this pinkies block off' I think to myself, I order the driver of the cart to turn back and go to that big building with the crowd outside it.
As we approach the crowd we slow down to a crawl forwards, so packed together are the pinkies to see the lumpen shape that is on the ground. I jump down from the cart, leaving the puny prisoner alone and shove through the crowd to the front, ignoring the protests of those I push aside like wheat in a field. Now at the front, I wait to see what this monstrosity, that dwarfs even I, could be.
As the man rips the hood off of the figure on the ground I suppress a growl of surprise as it is revealed to be a Minotaur. 'Is it dead?' I ask myself, scouring the body for any signs of life.
Basically 99% of this post works very well (and I should note this is not a criticism, as my early RPGing I'm sure was vastly worse) - the red bit is an example of information that should be GM's decision though, so the post would have worked better without the last sentence. Basically just remember to control your character and not the world around them.
