Hi Penmi,
I've got a 94 VH HC destroyer, and here's what worked for me:
*Getting 50% block is your first priority, so max shadow armor asap. You can block any attack - melee, ranged, magic. Try to buy, gamble, or find a shield with a lot of block.
*Socket all your gear with resist, armor, and crit gems.
*Update your gear occasionally, every few levels. Always check the blacksmith for upgrades when you're in town. Later in the game, gamble your gold away on gear, since you can't enchant as effectively as before. Gambling is a lot more fruitful here than in D2. I'm not saying to ignore enchanting, but slap on a few enchants, maybe 3-5 then stop or you'll probably wipe your stats (unless you have the gold to spare). I only enchant my uniques twice or thrice (none if I can't bare to see it wipe).
*Put 2 in str and 3 in def every level. I went 4 def:1 str because I have a 3000 dps sword I've enchanted prepatch, so the str isn't as vital in my case.
*Focusing on crit rate and increased crit dmg is wise in endgame.
*Make sure most, if not all, of you gear has lots of resists.
*Get elemental protection, and keep updating it with new ranks when they become available.
*Put 1 point in entropic aura when it becomes available, then max it when you start to feel unsafe.
*Use spectral echo as your main attack with a weapon or armor that has knockback. Hold shift and attack away from melee range, but just close enough for the spectral echoes to hit. Try to alternate putting points into spectral echo and crit strikes. Eventually you'll want to max spectral decay to double your dmg and have aoe stun/knockback.
*Keep an eye on your block rate when you have shadow armor up. Sometimes it doesn't work the way it should.
See here for explanation.
*Get titan stomp when it becomes available, then respec out of it when you don't need it anymore or have spectral decay.
*ALWAYS keep your defensive buffs up: entropic aura, frost shield, elemental prot., shadow armor.
Get this mod to extend their timers to 5 mins each.*Use heal spells to top off your health to save on pots.
If you choose to follow this advice and still get "oh shit" moments, don't worry because I also get them (once or twice per day) even with 5000 armor absorb and nearly 3000 in every resistance. Mobs that stampede (large packs of those orange lizard guys) and dragons are still deadly if I'm getting cocky.