You have already said you had a Blaziken, so I'm only going to guess that you know how to use it correctly. If you don't then take advantage of it's (kind of) high attack. Blaziken learns Sky Uppercut at level fifty-nine (I think?), but you also have Blaze Kick which is another amazing attack to have in your arsenal. For your other Pokemon, I would suggest having just three to a team, so you only need two Pokemon since you have that Blaziken. Swellow is an amazing choice to have on your team because of it's amazing speed and high attack. Ludicolo is also a decision, but it's also weak to flying Pokemon, but covers your Blaziken's weakness of water Pokemon.
Your team, Blaziken, Swellow, and Ludicolo, will cover alot of the games aspects and will be extremely good at a high level. Here I'm going to list a few movesets which can come in handy throughout the in-game opponents.
Blaziken is a very good Pokemon in R/S/E who can also learn amazing attacks to cover it's weakness'. Thunderpunch can not only take out flying and water Pokemon, but with high attack, it can be deadly to any Pokemon with neutral damage. Sky Uppercut and Blaze Kick are also choices because they are both STAB moves with high attack damage. Swords Dance for the obvious - To strengthen your Blaziken's attack.
Swellow is a fast, powerful ally to have on a team. Take advantage of it's speed. With that only it can take out defensive opponents such as Slaking and others. STAB Return on a Swellow is amazing, but you should only use it if your Swellow is extremely happy with you. Endeavor and Quick Attack is an extremely good combination - You use Endeavor when your low on health. Your next attack turn you use Quick Attack to get rid of the foe. STAB Aerial Ace for the obvious quick, flying move to take out your opponent.
Last, but not least is Ludicolo. Ludicolo is a Grass/Water hybrid Pokemon which can also cover it's weakness' - Take advantage of this also. Use Fake Out (Lombre, Ludicolo's pre-evolution, learns this at level nineteen.) to get quick damage on your opponent early in the game for damage and flinch. STAB Surf or STAB Giga Drain is also a choice here; Surf for the big damage or Giga Drain for some damage plus some health regeneration. You could then have Ice Beam to cover your Flying weakness and to take out other grass threats.
Have fun and sorry for the long read. :)