This is simply a build that I would typically run for consistent results winning.

Ghost is more appropriate for champions that can instantly jump on enemies such as Warwick with his ult. Volibear has no built in gap closers other than his Q, which makes it pretty obvious he is about to initiate. Flash give you the element of surprise, and one of the greatest things you can do in order to turn a game around on end a game is flash Q the enemy Adc or ap carry.

Take E level one to mitigate jungle damage, then W and Q at level 3 for ganking. Max W for a massive damage nuke, then E for slow and clear/aoe, and Q last. Of course level ult when possible.
Example of this here

Early level after red you want to just walk into an unwarded lane and start hitting the target. NEVER LEAD IN WITH Q unless they are about to get away, and never be afraid to use flash for a kill. Proceed to slow the enemy until they are low enough for you to execute with your bite.
In low elos the enemy often holds on to their flash until the end so be wary of that.

Attack speed runes are the best offensive runes you can run on voli, and I would ALWAYS take attack speed marks, armor seals, and mr glyphs whether it be per level or flat. Quints are choice and you can do whatever you want with them. You can't go wrong with AD, armor, hp, or attack speed quints.

Feel free to check out my stream highlights and past broadcasts to see how it's done at http://www.twitch.tv/blumintea.