Ok, here we go.
Try to make your sentences longer, use commas instead of periods. Imagine a storyteller telling your story to an avid group of listeners now imagine that each period is a place he stops to take a breath. Short sentences would have him hyperventilating to the point that the listeners would go else where. You also have to be careful you don't make your sentences to long, or our poor storyteller would pass out.
Make sure that each sentence flows on from the next. I noticed a couple of places in your story where it looks like the sentence order has gone a little out of wack.
Example: Maria came in with a deerskin from the deer Nicko had hunted the day before. It was freshly skinned and cleaned, and they used it as a rug in the cabin.
The way these two sentences are laid out makes it look like the deerskin is freshly skinned and cleaned....and leaves you wondering how does one skin a skin?
Actions speak louder than words. Try to make sure that when you move from one action to another that there is something there to link them together.
Example:
Nicko retired to his bed as his wife, Maria came in with a deerskin from the deer Nicko had hunted the day before. It was freshly skinned and cleaned, and they used it as a rug in the cabin. Nicko and Maria always made use of as much as they could of the animals they hunted.
Maria came to lay down with Nicko, for they had worked very hard that day in preparation for winter. “Nicko, do we have enough wood?” asked Maria, feeling anxious.
“Yes, dear.” Nicko replied
“We have enough fish, venison, right?” asked Maria, feeling more anxious.
“Yes, dear, we have more than enough for the winter,” assured Nicko “I have been out fishing all day, and hunting. We have everything we need.”
“Ok, I just want to make sure we always have enough.” Maria said calmly
“We always do.” replied Nicko,” Now, let’s fix some of that fish,”
Nicko placed some dried grass and some wood in the fireplace
How did Nicko get from the bed to suddenly building the fire?
Make sure you read through each paragraph to check that it flows smoothly into the next try not to make to many drastic changes in place or time. Take a few more sentences or paragraphs to slowly mold it together into a coherent thought.
These links might help a little, they can be found HERE (http://www.aaronshep.com/youngauthor/elements.html) and HERE (http://www.wikihow.com/Write-a-Good-Story)
Hopefully that didn't sound to harsh and critical, there is the bones of a good story forming here.