Upgrade to an eGo Vision Cleaomizer, aka "Stardust" aka CE4+.
Best $4 upgrade you can do.
The E1 "Revive" rebuildable tanks are also getting good reviews, although I haven't tried one myself. This is a real tank, not what is called a tank on an eGo-C. You can replace the innards for a couple bucks when they eventually burn out, and the tank body itself is replaceable. They fit the eGos and there are no cartomizers to mess with.
For juices, the best thing you can do is just buy 5ml bottles or "sampler packs" from as many vendors as you can. Finding the right juice is way harder than finding the right PV. You can read reviews until the cows come home but most of them won't be worth much because it's so subjective and everyone's taste is different. Any real bad juice makers get run out of here pretty quick, so anything you pick will stand a good chance of being decent. Only you can decide what's exceptionally good.