Tips to Use Faceless Void (Dota2)

• Mask of Madness will allow Faceless Void better to utilize Chronosphere throughout game, as does almost any item that gives attack speed or damage. A BKB is usually a good choice after getting a MoM as nukers outside the chronosphere can be ignored, while they otherwise burst the fragile Void very easily.

• When using Chronosphere it's important that you prioritize the targets to deal maximum damage. Important targets include carries and spellcasters.

• If you want to play your lane aggressively rank up Time Lock first, conversely if you need to play defensively rank up Backtrack after getting at least one rank of Time Walk as it is still your primary escape mechanism, while also having some offensive potential.

• Chronosphere will pause friendly units (exception : units under control of Faceless Void) and heroes as well as foes. Try to position it so enemies are within the sphere and allies are outside and can reach enemies inside without having to enter Chronosphere itself.

• Using later ranks of Time Walk and Chronosphere in tandem can easily catch entire enemy teams off guard.

• Although Faceless Void is a hard carry hero, he is extremely supportive when using his Chronosphere as it has the potential to trap the entire enemy team in place for many seconds, allowing easy use of several ranged ultimates altogether for massive damage. Example: Lich, Jakiro, Witch Doctor and Gyrocopter ultimates.

• If you are trying to decide on what item build is best for Faceless Void remember that his main goal is to do the most damage and hopefully kill at least one key enemy hero inside his Chronosphere where he has a 5 second free reign to attack a target without any chance of retaliation.

• While Aghanim's Scepter may diminish your carry potential sometimes it might come in handy as it increases your Chronosphere duration to 6 seconds and reduces its cooldown to only 60 seconds, allowing your ultimate to be ready in almost any team fight and while it may not contribute to your damage output very much it does increase your survivability by granting you stats and HP. 

source: http://dota2.gamepedia.com/Faceless_Void