Hey there!
You've got a nice looking team here! But for competitive Pokemon we usually like to see things like the Pokemon's nature, EVs, held items, etc, so the raters can have a good understanding of your Pokemon and be able to give you the best rate possible. But since you're still working on your team, I'll just recommend a few simple things to start.
Serperior LvL 37 ( Ovibously )
Leaf Blade
Leech Seed
Mega Drain
Coil
Serperior's physical movepool is pretty shallow, however, if you'd like to use Coil, there's still a fair amount you can do. Since Coil boosts Attack (as opposed to Special Attack) you definitely want to replace Mega Drain. Test out Substitute, Coil, Leaf Blade, and Dragon Tail. This way, you can switch into Pokemon that Serperior can handle (Alomomola etc), set up Substitute, and boost away with Coil. Leaf Blade becomes your primary STAB, and because Serperior has the advantage of being faster than most phazers in it's tier, Dragon Tail pulls the set together, making Serperior a good defensive pivot in play.
Zebstrika LvL 35
Volt Switch
Charge
Charge Beam
Spark
P-Sign already covered Zebstrika, but for chronology's sake I'll go a bit more in depth. There's kind of only one thing Zebstrika can do -- Attack. So while you're on the right track, there's still a few things Zebstrika needs to be at its best. For one, I recommend this set : Thunderbolt, Hidden Power [Grass], Overheat, and Volt Switch. Thunderbolt is self explanatory, and HP [Grass] can help take out bulky Waters like Quagsire who resist Zebstrika's electric attacks. Overheat is just an overall good coverage move, and finally Volt Switch keeps up your offensive momentum and goes in tandem excellently with Choice Specs, Zebstrika's recommended held item.
Unfortunately, I don't have time to finish so I'm going to leave this rate alone for now. Please let one of the raters know if you want a more competitive, in depth explanation or recommendation for your Pokemon.
Best of luck! :>
EDIT :
If this is an In-Game team and you don't plan on using your Pokemon competitively, than check out the In-Game Team Help section of this forum found
here. The raters there can give you way more relevant advice for your team. Again, good luck!