Welcome to the forum. What got you interested in this hobby(I'm sure we'd al like to hear about it). To me one of the most important and usually overlooked thing is to clean your RC after every run with cleaners that don't harm plastics(a fast drying cleaner is best). If you need to spray anything near the electronics make sure it's electronic safe or at least cover the electronics so they don't get wet. After every run inspect everything to make sure nothing is loose. Also check for any binding on parts that should freely move. As far as batteries make sure you charge or discharge them according to the manufactured recommendations using the correct type of charger. I use tire dressing on the tires when I'm storing them for awhile to ensure the rubber don't dry out and crack. If you run your RC a lot I would periodically check the shock fluid, make sure diffs are lubricated, lubricate tranny of required by manufacturer, check all wiring on all electronics after every run to ensure all wiring is intact (no loose connections or frayed wires). Keep wiring neat and in order and make sure they don't touch anything that moves(drivetrain parts for example). Don't over gear or under gear your motor. I'm sure there's a lot more I didn't list here and I'm sure you'll get more tips from the other members.