You already know what not to do - Don't tilt and don't try to make hero calls on river. This will save you alot of money at NL25
My personal experiance in making money at NL25 is to be patient, wait for premium hands, play them aggressively, and watch out for draw heavy board - here you might wanna slow down depending on the action. If you have stats on villian then exploit them. But basicly stick to a kind of ABC poker with a little aggression and you'll be fine.
Looking forward to hear about your progress