As far as division of space and eye-rest is concerned, I consider these tips to be important not always. I've seen quite a number of very good symmetrical images. Also seen some that were heavy in detail but nice and interesting to look at nonetheless.
I am all thumbs up for the first three tips, but find the last two to be quite subjective really. I would exchange one of them with "under-lighting / overexposing" because that's a serious disadvantage.