As others have said, keep a record of the times and durations of the fits and, of course, ensure that the area around your dog is safe for him. He won't be able to hear you during a seizure but you might still want to talk to him anyway, so that your reassurance is there for him as soon as he starts to come out of it.
I also suggest keeping an accurate record of exactly what he eats (and when). One of my cats started having epileptic fits around last Christmas but then didn't have another until January 11th, followed by a further one on January 17th. Looking back, I realised that all of his seizures occurred within a few hours of him having eaten sardines. Obviously I've not given him any sardines since then and, fingers crossed, he's been fine since then.
My friend used to have an epileptic German Shepherd. Once the vet had got his medication sorted out properly, he was absolutely fine and he lived a long and happy life.