What type of filter, heater, lighting etc that you are using. Brand names & models are a good start. With the filter, what is it's rated turnover if it's a canister, internal or HOB.
What type of substrate will you use if you have one in mind. As well as hard scape, i.e plants, &/or driftwood, rocky caves etc.
Finally your water PH, GH & KH. You can take a sample of water to a good LFS and ask them for these measurements.
While you find all this information out for us, you should go to the Library section of this forum and read about how to cycle a tank in the Chemistry section. There is a lot of good stuff to learn in the Library section.