A little use of your time will help your aquarium. One important thing you should do is water changes. This means taking out a portion of your aquarium water and putting new water in. You can either do a 50% water change every month or if you have a lot of fish that make lots of waste, 25% every week is recommended. Water changes are helpful because you are taking out excess nitrate and organic material(poop) out of your fish tank. If you don’t, annoying and ugly algae will grow and make your tank look ugly. A little algae is ok but too much means you need a water change. You can either do a water change in the middle of the water column or if you see a lot of poop in the water, do water changes in your substrate/gravel to remove poop. In order to do a water change, you need a hose specialized for it such as this:
Make sure you turn your filter off during a water change. After doing a water change, fill up your tank with tap water from your sink. Chlorine takes a few hours until it kills your fish so add some dechlorinator or water conditioner to kill the chlorine. I recommend using Seachem Prime. A good demonstration on how to do water changes is included here.