Something my paed always said that I found very true, was that bubs not only need a lot of rest, but when they are ready to take steps forward, they do. So we learnt to take our cues from our little man (8wks prem) and he always took leaps, but only when he was ready. So we used to let him latch and be fed through the NGT as much as we could so he could associate the food with the breast. And as he got stronger he would have a little lick and suck while still getting the NGT feed.. seemed to help him progress!!
Another interesting thing we found was that he feeds better in a really quiet place. Apparently after all the noise in SCN/NICU's premmies like the quiet and it works for us. Reduces the over stimulation which is what seems to tire them out so much.