I'm playing a Wizard with Abjuration/Counterspell specialty school right now, but I don't have much advice since he's only just now turned 6th level and hasn't dispelled/countered a single spell yet.
So I'm also curious to see what can be done to get some mileage out of the concept of a master of counterspelling. Counterspell Mastery will make it a reactive ability a limited number of times per day, but otherwise you wind up having to ready an action to counterspell.
The Arcane Savant prestige class eventually gets Dispelling Mastery, allowing spontaneous conversion to Dispel Magic and Greater Dispel Magic, but going that route makes you lose pure Wizard levels and so your Counterspell Mastery will be fewer times per day overall.
I'd like to know what ways there are to increase the caster level check to dispel/counter. I'm not up to speed on what methods (if any) there are to boost those checks, as that would seem to be the key problem with counterspelling - it isn't particularly reliable against casters who are close to your level.