How do I bring up topics about housekeeping and cleanliness to my SO without being accused of nagging?

I have been living with my gf for a little over 3 months now and while I am definitely not a “clean freak”, I think that I am slightly more concerned about the cleanliness of the apartment than she is.

Last night I brought up the fact that she will often leave the sponges in the dirty sink filled with nasty dish water after washing a dish and asked her if she could try to remember to rinse it and leave it out of the sink and one other thing and I really didn’t think I was asking it in a rude way and she got really mad and accused me of nagging and I told her I wasn’t trying to nag but was just asking and it was the first time i’ve ever brought this kind of situation up.

I do, not all, but in my opinion, most of the cleaning in the apt. and after doing all the dishes in the sink today wanted to just ask her to make sure she wipes her plate into the trash before she puts it in the sink because our sink was so discusting with big pieces of lettuce and some sort of cheese substance but I want to do this where she doesn’t get upset and think I’m trying to make her mad. Any suggestions?