Rock in the bottom, then sand then water. Cycle it with raw shrimp, raw fish or liquid ammonia. I highly recommend a good quality skimmer for that size tank. Do as much or as little rock as you like the looks of. To save on money, use mostly base rock and seed with some LR. I used all LS because I like all the tiny shell fragments and stuff that comes in it, but you can use pool filter sand to save on costs. If you're planning a reef, led lights cost more upfront, but are efficient, give off less heat and don't need bulb replacing. Taotronics are good LEDs from what I've read.