The Elite Four Guide

This is a guide to the Elite Four in Pokémon Ruby and Sapphire. It includes hints and tips on some recommended Pokémon types and moves and a list of the Elite trainers Pokémon team. If you are having a little bit of trouble with the Elite and the Champion, read on!

Elite Four #1: Sidney

Sidney is a user of Dark type Pokémon. His team includes:
Mightyena - Level: 46
Shiftry - Level: 48
Cacturne - Level: 46
Sharpedo - Level: 48
Absol - Level: 49

One type that would be great in this battle would be Fighting type. It is super effective against all 5 of Sidney's Pokémon. If you don't have a Fighting type however, try and play for some other weaknesses.
Bug Type moves are excellent against Shiftry and Cacturne, as Bug type is super effective against both Dark and Grass type. For Sharpedo, you could use its Water type against it by using Electric type attacks.

By beating Sidney, you gain access to the next Elite Four member; Phoebe.

Elite Four #2: Phoebe

Question: Why is Phoebe dressed like that when she trains Ghost types? 0_o
ANYway... Phoebe raises Ghost type Pokémon, as I said earlier. This is her team lineup:
Dusclops - Level: 48
Banette - Level: 49
Sableye - Level: 50
Banette - Level: 49
Duslops - Level: 51

This battle can be a little tricky. All of Phoebe's Pokémon (excluding Sableye, we'll deal with him later) are super effected by Ghost and Dark type attacks. So, a good Ghost or Dark type move will go a long way. But beware, if you are using a Ghost type in this battle, Phoebe's Pokémon also get an advantage thanks to the Ghost type’s effectiveness on itself. So, just be careful.
Now, about Sableye; it has no weaknesses, so don't bother using your crafty Ghost or Dark type moves... it'll make no difference. I suggest just going all out and using your most powerful moves, no matter the type. (Except Normal and Fighting types! They won't hit it at all!)

For beating Phoebe, you are allowed onto the next Elite member; Glacia

Elite Four #3: Glacia

Glacia, as her name suggests, is a trainer of Ice type Pokémon. Her team is as follows:
Glalie - Level: 50
Sealeo - Level: 50
Sealeo - Level: 52
Glalie - Level: 52
Walrein - Level: 53

Glacia's Pokémon take full advantage of Hail, a move which deals slight damage every turn to all non-Ice types. It can do some damage in a long battle, so try and knock out her Pokémon quickly. For her two Glalie, Fire and Fighting type moves are great. Steel and Rock can also be used, but aren't as recommended. If you're using Fire, make sure to put them away for when her Seal Pokémon come out, as they are part Water type.
For Sealeo and Walrein, it would be best to continue using Fighting type moves on them. Also, you can counter their Water type with a good Electric or Grass type move. Rock types are also effective, but watch out for their Water and Ice type moves.

For beating Glacia, you are granted access to the final Elite Four member; Drake.

Elite Four #4: Drake

Drake raises Dragon type Pokémon. His team includes:
Shelgon - Level: 52
Altaria - Level: 54
Flygon - Level: 53
Flygon - Level: 53
Salamence - Level: 55

Two words: Ice Type. Ice type moves such as Ice Beam are the absolute best thing to use in this battle. Not only is it effective against Shelgon, the pure Dragon type but even better against his Dragon/Ground Flygon and Dragon/Flying Altaria and Salamence. If you neglected to get an Ice type Pokemon or attack, Dragon type would be your next best bet. But beware, similar to the Ghost type, Dragon type is super effective against itself, so you're giving Drake an advantage if you send out a Dragon.

For beating Drake, you are led towards a walkway (a very long one at that) that will lead you to the Champion!

Elite Four Champion: Steven

You've met Steven a few times before, nows your chance to battle him. You could say his main Pokémon type is Steel, but he also has a few Rock and Ground types too. Any which way, he uses Mineral Pokémon. ;) His team includes:
Skarmory - Level: 57
Claydol - Level: 55
Aggron - Level: 56
Cradily - Level: 56
Armaldo - Level: 56
Metagross - Level: 58

We'll have to take most of Steven's Pokémon individually, as there is really no universal type that will conquer his team. Here, to make it easier; I'll give you a list: xD

For Skarmory: For this metal bird, Fire types are an obvious option. Electric types are also equally effective.
For Claydol: Ok, Water is probably a good type to use here. Ice, Ghost and Dark are also good options. A Pokémon with the Levitate ability or a Flying type would be good here, to avoid it's powered up Earthquake attack.
For Aggron: Fighting and Ground and extremely effective against Aggron, so go for those. I would avoid Water types however, as Aggron knows Thunder and Solarbeam in an attempt to counter them.
For Cradily: Ice is great here, as Cradily is Rock/Grass type. Again, Fighting can be used as a backup. Be careful when using Ice types though, as Cradily knows the move Ancientpower, a Rock type move which can seriously hurt your Ice type.
For Armaldo: A tricky type combo here, it's Rock type makes Fire almost useless against its half Bug type. So, I would probably go with Water type here. Steel as a reserve.
For Metagross: This is the one you want to keep your eye on. Meta's Psychic type makes Fighting moves not so great, so try and hammer it with Fire and Ground type moves. But beware; Meta knows Earthquake to combat Fire, and has some other powered up moves like Meteor Mash and Psychic to deal with the Grounds- even though it isn’t type effective, those moves can seriously hurt you.

After this; Congratulations! You're the new Champion!