Early Game Strat Build #1
This build is meant to push the lane as hard as you can while still having the ability to kill. Kill towers fast by blasting Creep waves with your tombstone and start whittling at the tower and keep going until enemy reinforcements come to aid. At that point just go to other lanes and continue the same until all tier 1 towers are gone.
Mid Game Strat Build #1
By mid game you should have at least a completed vanguard and perseverance and mana boots. Obviously on your way toward your Bloodstone. Keep up the tower push and poke with Decay.
Late Game Strat Build #1
By this point you should already have your core plus 1 late game item. You should be feared as L4D style "TANK!!" You rolling into the enemy team should be feared as your ultimate just makes a team fight go well into your favor. The more you stay up, the more your Decay will just grind your foes to their grave. At this point your Soul Rip should just be your Heal, you being alive longer helps more than a 500 damage nuke, but in very small cases nuking isn't that bad, just remember to prioritize it as a heal.
Early Game Strat Build #2
Getting a clarity to start the game will increase your nuking potential by alot. Harassas with decay and soul rip, Prioritize the carry, if no carry then look for the one guy without regen or very little
Mid Game Strat Build #2
Once again your items should be close to your Core, if not already finished. Start working toward things that amp your nukes, Like Orchid or Dagon....Yes Dagon. With your ultimate Dagon on Dirge is fearful early into mid. Even Late game it still does a decent amount.
Late Game Strat Build #2
Your Core is finished and your done with at least 1 late game item. Your focusing enemy carries with your massive nukes and annoying the **** outta the rest of your foes. Bring them down to their knees and make them beg for mercy.