Hi there, welcome to our obsession LOL
For a tank that new you should be doing a 20-30% water change every week. Make sure you do not rinse the filter media in tap water. If you clean out the mechanical parts of your filters, take the sponges, carbon, etc and put them in tank water. If you clean them in tap water you will kill off your beneficial bacteria.
Here's some good reading on maintaining a healthy tank:
I know I did not give a lot of info, but this will get you started :-) There are others on here that are much better at explaining the info you seek.