Aquascaping (the arrangement of the rocks) is really up to you and what looks good to you. You do, however want to leave crevices and holes in yoru rockwork so that your fish can swim through them, and so that you get adequate water circualtion through the back of your rock wall. I use the fast test kit from Aquarium system and like it very much. You can get at kit that tests for ammonia, nitrate, nitrite and pH for about 40 or 50 bucks at your lfs. You should also test for salinity using a hydrometer, adn of course temp. As for schedule of testing, now would be a good time to start, because your tank has been up and running for awhile. I test my water parameters about once every two weeks now that the tank is established. While it was cycling thought, i would test about once a week.
HTH, good luck
Jon