Okay, first, if your having trouble, you'll probally want both of your pokemon higher than the gym leaders highest, meaning you'll want to train them both 2 levels.
You should have....
Pidgey: Level 14
___
Moveset:
Gust
Sand Attack
Tackle
Quick Attack
And
Quilava: Level 14
_____
Moveset:
Tackle/Leer/Smokescreen/Ember/Quick Attack
Tackle/Leer/Smokescreen/Ember/Quick Attack
Tackle/Leer/Smokescreen/Ember/Quick Attack
Tackle/Leer/Smokescreen/Ember/Quick Attack
Thats what you should have, at this point in the game, I reccomend
Ember Quick Attack Smokescreen Leer
Anyway, All your really gonna need for this is Ember.
Start off pidgey vs. pidgey , and just use quick attack over and over until Falkner's pidgey faints, Here comes Pidgeotto.
Keep abusing Quick Attack, using it over and over, until pidgey faints.
Pull out Quilava, Raising him to level 14 let Cyndiquil evolve, so he should pretty much be able to murder pidgeotto with ember.
Just keep using ember here, and you'll be good.