I got 4 ascensions back when I was 18 (I think) and discovered Nethack, but haven't really played it since. I think it was Val/Wiz/Bar/Sam, if I remember correctly, after which I stopped playing since each playthrough was just turning out too similarly. Key pointers: as in all roguelikes, caution. Be thoroughly spoiled for Nethack's many "here's something to kill you that you could never have predicted!" moments. Never be afraid to flee; be VERY careful about wasting your potions and scrolls in water, and whenever you find yourself interacting with one of the game's more obtuse systems (breeding, dancing and pets come to mind) or any of the "two-hit death" things like drowning, petrification etc, CHECK THE WIKI. Good luck!