I find, generally, people tend to get Steamboots + Bottle on him, and then either Assassin's Shroud (survivability), Shieldbreaker (synergizes with his ultimate), Frostburn (for chasing purposes)...really, it depends on what your team needs. If they have a Swiftblade, then you might consider making a Geometer's Bane. If they have a hero with high evasion, then you'd want a Savage Mace. If they have Plague+Keeper constantly shielding their allies, then heck, maybe you'd want to make a Harkon's Blade. (No one likes trying to kill a hero with 25+ armour - or you can make a Nullfire Blade and just purge the buffs off of them)
There's no real "make these items in this order and you win" strategy, you have to use your judgment...a counter to everything.
As Artemiye covered earlier, it really depends on what the enemy team is. You should always build your items based on the enemies team line up. Another very good option early on is Shaman's headdress if their team is rocking a lot of magic damage. You have to remember that the majority of your early game power comes from power conduit.
Bottle is a must on him in my opinion since he is a very strong ganker and needs bottle to support him.
My starting items depend on who I will be going mid against usually. It almost always includes runes/potion and either 2 crowns of the pretender (which will become soulscream rings) or battery depending on who I think will be mid. Then a straight rush to bottle and phase boots.
Corrupted Disciple isn't your average ganker/carry. He specializes in survival, just like sand wraith and zephyr. What this means is- When you're building him, he already does very, very heavy damage. All you need to do is survive, and the damage will come all by itself.
This means you need to survive. Don't bother getting any, and I mean any attack items, and purely go for defense.
I start with:
2 Runes of the Blight / 4 Minor Totem / 1 Pretender's Crown
--> Bottle ASAP (Ship with courier)
--> Steamboots (You need +10 Strength [+190 HP] a LOT more than you need +24 damage)
From here you can go a few paths.
--> Bracer (If you're not doing too hot)
--> Helm of the Black Legion (If you need mass HP, badly)
--> Barbed Armor (If you need armor badly)
--> Shaman's Headdress (Against a very pushy team)
Then after this set...
--> Shrunken Head (Against a very CC happy team)
--> Geometer's Bane (Mostly for the extra movespeed, but also illusions are good)
--> Nullstone (Against single target heroes)
Honorable Mention: Frostburn. I don't know how good it is after the patch, but I used to get it at about the time I would get a geometer's, if I was even going to get it (Slow + Nice HP boost + Movespeed boost, really. That thing does shitastic damage anyways)