I have a history of bad apartment ovens, and at least 2 dorm ovens. The two things I can strongly suggest are a thermometer, so you can know with some certainty that when the oven thinks it's at 350 the temperature in the oven is actual 350. Oven temps will peak and valley around this number, but should normally withing 5 degrees in "good" oven, but I've had one with a 15 deg F variance.
One other thing would be to add some mass to the oven (thermal sinks). My go to is a pizza stone, but I know some people who would wrap bricks in aluminum (fireplace bricks recommended). Cheaper ovens hold less stable temperatures, and the added mass helps stabilize oven temps. Flattening the peaks and valleys of oven temps will help tame a bad oven. After it's tame you might find that 350 is actually 375, and you will have to adjust down now that peaks in temperature are less likely. Your preheat time will get longer with the additional mass in the stove.
I've read that the type of oven can affect the bake. An electric oven being one of the dryer ovens, while burning gas can create small amounts of water vapor. Professional bakers' ovens often use steam heat, creating a very moist environment for baking. You can add a tray of water, usually on the lowest point in the oven, to create steam. I've done that for bread baking. Bonus: the water will also act as a heat regulator, like the pizza stone.
All else fails you can pull the cookies earlier, or ball cookies to make a large center mass that could cook slower.
Good luck and enjoy the challenge of dorm cooking.