If you want to mill like a pro you have to think fast. These cards require you respond to anything that comes your way.
Sands of Time
This ancient Artifact is hard for many players to understand. It provides advantage for you as long as you control your Commander. You can activate tap abilities during your upkeep and let Sands Untap your creatures. It allows your creatures to make up for the turn they were summoning sick, while most of your opponent's creatures get another turn to rest.
Run it with Mesmeric Orb and if they want mana untapped they'll have to mill for it.
Copy it to Stasis opponent's creatures and give yours an extra untap each turn.
Don't mix it with Intruder Alarm if you're using it for defense.
Umbral Mantle
This Equipment is about as tricky as you can get. To use it effectively remember that the untap itself is a cost that can't be responded too. Tap to mill a player and activate to Untap then let each +2/+2 Ability Resolve before repeating the process. When you're done Phenax's mill ability will see the Toughness the creature ends the sequence with rather than what it had when the ability was activated.
For reference with a 2/1 Rat and 9 mana you can mill someone for 28. If it's Grimoire Thief you'll take 44 cards out of their library and for 12 mana you can make that 65.
The equation for this interaction is Cards Milled = (T+M2/3)(M/3+1) where M is the mana you have to spend and T is the starting toughness.
Intruder Alarm
Almost always good to play. This deck includes enough creatures to make up for the restriction on untapping them normally and your opponents may think twice about playing a creature if i means them milling 10 or 20 cards when it lands. Thousand-Year Elixir will also allow you to get a tap out of new creatures as they land since the Alarm only triggers after it enters the field.
Play it with Forbidden Orchard to grant untaps on your timetable or Undead Alchemist To tear creature decks to shreds.
Or if you just like keeping things under control King Macar, the Gold-Cursed, or Avatar of Woe can remove every new creature that hits the field.
Be careful playing it against Green though, they tend to dump their hands to it.
Necrotic Ooze
Obviously this card is insane. Tree of Perdition is one particular offender with this out but if you happen to have Pili-Pala and Deranged Assistant (Removed from Deck) in your Graveyard the Ooze can put your whole library into your yard at mana ability speed. Make sure and get good use out of it before Kozilek, Butcher of Truth puts it back. You should be able to win before then. Remember that Ooze can use Eater of the Dead's ability to untap off of creatures in your graveyard too. Which may be useful after Necrotic Ooze is a 4/40.
Mikokoro, Center of the Sea / Geier Reach Sanitarium / Cephalid Coliseum
The Banes of your existence are decks containing Kozilek, Butcher of Truth and/or Ulamog, the Infinite Gyre, but once your mill power is high enough These instant speed draw lands allow you to stack sweet victory on top of bitter disappointment. Then you consume the victory first and leave the disappointment for never.
Plus they draw you cards if you need them.
Tormod's Crypt
Good for a bit of control over who gets what, Tormod's crypt lets you remove an opponent's Graveyard from the game.
You have to be pretty selective about its use though. Your reanimators can often get more use out of a graveyard than an opponent and Consuming Aberration and Sewer Nemesis rely on cards remaining within.
Keep it in play until your opponents target something dangerous or trigger an Eldrazi Reshuffle.
That said, don't be afraid to slap it on a Prototype Portal.
Disallow Tale's End
As the only vestiges of true blue in this deck Disallow and Tale's end have all sorts of unpleasant uses. Countering spells is one particularly heinous function. Additionally, the Stifle side of each lets you do far more than simply counter an Aetherflux Reservoir activation or a Storm trigger.
Sands of Time causes an opponent to skip his or her untap and since you'll be receiving priority after the active player you are well within your rights to ask if he or she will be tapping lands in order to have them untapped by the confusing artifact. Targeting the sands trigger at this point allows you to essentially counter an opponent's turn.
(I can't be held responsible for their complete loss of all trust in you afterwards though.)
(Post Commander death trigger rules change this next bit actually works! It didn't when I wrote this originally due to rule 400.7h)
If you have the mana after fogging a creature with Mystifying Maze(Removed) consider countering the delayed trigger at the end of their turn. Remind them that you asked where they were putting it when it was exiled and take satisfaction in knowing that the next game in which you Maze their leader they'll be buying it out of the Command Zone. It's gone for the rest of the game. On a related note always counter Norin the Wary's return trigger, no deck that plays him plays fair.
Disallow is also particularly useful for countering the Triggered reshuffler abilities on Eldrazi Titans... all the same, it makes me uneasy to see one laying in the graveyard.
