I worked for a swimming pool company for better than twelve yeras and have had my fair share of putting in pools as well as repairs and what not. I am not going to try to discourage you from getting a pool but I can say that as long as I live there will be no pool for me. I am still traumatized from the pool business.
The biggest tips that I can give you are, as already stated, level level LEVEL. I would personally get my hands on a transit, duct tape a measuring tape to a pole (we had a tamper that was broken that we used as a foot so that we didn't have to hold it) and only put a pool on level unexcavated ground.
In my area, fine masonary sand was the bottom of choice. 6" cove going up the side of the pool. Some people used something called Poolcrete as a bottom but sand is a whole lot cheaper. Use patio stones under each upright (1' X 1'). After you have the bottom track and uprights all put together have a guy or two help you will the pool wall, they are heavy and if it is windy you will have a heck of a time handling it. After that's all put together and you're ready to drop the liner. put the liner in and if it is an overlap liner just make sure that it is even on hte outside of the wall the entire way around. Then take a shop-vac and put it in through the return hole in the pool wall and duct tape the skimmer hole shut. Turn on the shop vac and it will suck the liner to the wall and then you can adjust it so that there aren't any wrinkles. Fill with water and wait two days to get in it, if you are in it too early the sand will be soft and you will get footprints in the sand.