Every pool needs to be winterized before winter, especially the gunite pools as they are the ones that are made of cement walls and coated with plaster on it. So, If not winterized properly they can form cracks. I built mine around 10 years back from a wonderful gunite pool construction team(http://www.ferraripools.com/what-we-do/pools/ ).
These are the few steps I take to winterize mine:
First I test the water in the pool. I use a common swimming pool test kit to test the pool water.
And then apply pool shock in order to circulate the water in the pool. Important thing-this should be done while the pump is running so that the water is circulated evenly throughout the water. I run it for about 7-8 hours.
After circulating the water I apply some algaecide to allow the water to fight off the growth of algae.
Then I set the pump to backwash the water so that it will clean out the filter and the pump.
Then, I let the water to drain out using a sump pump below the surface of the water setting the drain hose away from the pool. The important thing is to drain the water below the level of tile, if you have one, to avoid the cracking from the freezing water.
After the process is done, remember to drain water from the hoses. A shop vac can be used to blow out the water from pool hoses and use water plugs to avoid the water entry in the lines.
Finally, use a good quality and durable pool cover and spread it over the lengths of the pool.
If you have any more suggestions, please let me know...