my best piece of dessert advice is this:
if you want to wow people with a cake but aren't confident or don't have the time/energy: bake a box cake, but make your own frosting from scratch. Look up a decent recipe online.
the frosting for a cake makes a much bigger difference with store bought vs home made than it does for the cake itself.
even if you just make a simple american buttercream, no eggs or heat involved. BIG difference.
also, people appreciate looks for dessert, so if you make it cute then people will think it tastes better too. just keep it neat as possible and add some sprinkles or artfully arranged nuts to keep it simple (piping is not always accessible i know).