Level 39 Valor in Oz here - the ones you want to concentrate on are those that she says "simply amaze" her (the IVs will be over 80%). She'll read out the pokemon's highest stat first (HP, Attack or defense or a combination of two or all three). If she says she is blown away then the stat will be 15 (highest you can get), for any that are excellent it will be 13-14 (anything below this is not as good).
If she says that HP is the strongest feature & she is equally impressed by both Attack & defense, and is blown away by the stats, this will be a perfect (100%) IV Pokémon for Valor.
Have a look at Poké Assistant (pokeassistant.com) & try appraising your mons using the tools they have available so you know what your IVs are & can concentrate stardust & candy on ones that have good IVs.