Surf
Ice beam
Earthquake
Rest/Protect
Surf is a standard Sp.Atk move plus STAB, and since Walrein has higher Sp.Atk than Atk, all Walrein should probably know Surf.
Never teach a Pokémon two attacks of the same type (like teaching Walrein both Ice Beam and Blizzard), because the foe may have high defense against both moves, reducing your offense options. Ice Beam beats Blizzard, because in 2 turns you can use Ice Beam twice and deal that much damage, while Blizzard may miss once or twice, overall dealing less damage than Ice Beam in those 2 turns. During those 2 turns, your foe might've KO'ed Walrein already.
Earthquake is a standard Atk move that many Water Pokémon should know to cover the Electric weakness.
If Walrein holds a Chesto/Lum Berry, teach Rest; if it holds Leftovers, teach Protect.
Chat with our AI personalities
There is actually a few things you can do after beating the elite four on Pokemon Emerald Version. First, you should go all around Hoenn and listen to the people who have heard of your outstanding achievement of defeating the Elite Four the the Champion. Then, the next time you see Scott, he will bring you to a place called the Battle Frontier. There are 14 more badges to get over here (or is it 16?). WARNING!! Defeating the Battle Frontier will take you an extremely long time and WILL be frustrating. Just keep on battling and you will do it.
Earthquake Flamethrower Rock Slide Take Down/Hyper Beam OR Earthquake Flamethrower Sunny Day Solarbeam The best thing about Camerupt is its high Atk and Sp.Atk, so you should take advantage of that if you choose to use Camerupt. However, with its low defenses and Speed, it can easily faint to its quadruple weakness Water, so Camerupt isn't recommended for use at the Battle Frontier.
At the Battle Fronitier a house with 2 old ladies. One of them should teach you thunderpunch for the right amount of Battle Points.
Earn battle points(BP) by competing in the; Battle Tower, Battle Dome, Battle Palace, Battle Arena, Battle Factory, Battle Pike, or Battle Pyramid. Once you have earned enough BP then you can visit a house that is all the way to the right of Battle Frontier. It should be north of the Battle Factory. Then talk to either of the old ladies and they will teach your Pokemon moves in return of BP's.
I'm no expert, but I'd say that you need to tell us more. What are their moves? Stats? Held items? I'd say swellow sucks and you should replace it with flygon or salamence or skarmory as your flyer and replace azumarill with a crawdaunt or gyrados or walrein.