Survival in Abyss tends to be more about avoiding your threats and getting away before they build up into something extra lethal. Wiping the threats out works too. I prefer an overwhelming attack capacity to stealth, but both are good if you don't get complacent. This
video was linked to in an earlier thread. Despite having a lot of DCSS experience, and a multitude of options to choose from, this trip was a wreck. Don't rush your decisions when in a bad situation, especially in Abyss.
Try not to stay within LOS of any of the following without reliable escaping or killing methods:
1) Starcursed masses
2) Spatial maelstrom
3) Wretched stars
Burn up blink scrolls when there is no better way out, however many are necessary. Same goes for wand charges, evokable summons, ambrosia, everything. Seriously, no amount of consumables is good when your char gets slaughtered. It also never hurts to have a few fog scrolls on hand, they're beyond useful in any branch.