I am not sure what kind of spec you are using but I assume that you got a Talisman build since you got 53 points in the Desecration tree. DT pretty much lives from getting crits, critical rating is very important so your gear should have lots of critical rating. These critical hits will help proccing the AA talent Void of Madness which is a must have for every DT, I have never actually seen anyone run other AA talents since they are all kinda crappy. So if you still have enough AA points get that feat, then max out the AA perk for critical rating, everything else comes after that.
Since Talisman specs got increased crit chance on Blood for Aid you can keep the 2 highest ranks of that combo constanly on cooldown, also use the highest rank of Leech Life and A Soul for our Feast, that will increase your health tap like crazy.
What’s also important: Ritual Bloodshed must be on cooldown all the time to keep the stack at x10. That will increase your overall damage and give more health tap. Obviously, Shadowhex must be on cooldown all the time in combat too.
It basically boils down to: Keep Life Leech buffs up all the time (Bloodshed buff and Life Leech combos), spam Shadowhex as much as you can and spam Blood for Aid as much as you can.
EDIT: I am by no means a DT expert but talisman DTs are really not that hard to play, the way I described above I am able to easily tank in most dungeons and raids, there are probably people that know more tricks but I never really needed to do anything different because Void of Madness makes DTs totally overpowered once you got enough gear to “support” it with your critical rating (topping DPS while maintanking and even healing more than healers in certain fights).