Egg Quality Issue. Improve egg quality?

Hello Doctor, I am trying hard to get pregnant from last one year but not been successful. I have also done 3 IUI cycles and one IVF and all have failed. All my tests are normal and doctor can't figure out a reason for it apart from my advanced age (38). My AMH is 4.3. In my last IVF cycle, 14 eggs were retrieved, out of which 12 were matured and 9 fertilised however only 1 became a grade C embryo. The remaining were slow and didn't grow as expected, hence the doctor had to cancel embryo transfer. Now I don't know what I should do. I have been asked to improve lifestyle and try naturally. Is there anyway to improve egg quality ? Any recommendation of what I should do to get pregnant. I am extremely disheartened as there seems to be no solution yet.