Get the ground as level as possible, then level it further. Keep leveling until it's perfect, or until you end up with an inground pool.Don't use sand, it will shift. Filling in low spots WILL end up giving you low spots again, as the weight of the water will compact the ground tighter than you can pack it.
Ditch the pump & filter that comes with the Intex and get a real filter & pump. I picked up this one at the pool store and have not regretted it- I've saved that much money in filters, and not had green water, and can vacuum- something that those little Intex pumps aren't strong enough to do.(mine's only ½ horse though)
http://www.columbiapoolproducts.com/entry-level/
Get a GOOD test kit- I have the TF100 and find it easy to use, accurate, and the support here is fantastic. The test results are usually in line with what I expect, and I always get expected results from chemistry adjustments. I doubt that would happen if it weren't a good kit.
Put something under the pool if you can. All my budget would support last year was ¼" fanfold foam, it made a difference and was better than nothing. I've read that thicker foam feels better, but I've not tried it.
Stay on top of your chemistry, mine turned green last fall and I gave up until this past weekend. It's progressing, but it's work. Covering it would have helped.
Read pool School several times, and don't worry if it doesn't all sink in. Just keep reading posts and threads here and it will eventually "click". Then go back & re-read Pool School, it will seem like second nature.
Good luck, and welcome aboard!