My first post here
I was there too.
I got to 100, had a few pets and figured Id have a look at the menagerie.
My highest pet was 14 at the time an Azure Whelp.
The outcome motivated me to get some 25s.
Luckily I had a bit of a head start through having collected pets long before the battle pet addition to the game, and I have sat on max gold for ages due to not playing seriously (no cost) and mining/herbing through the last expansions.
I followed the Arcane Eye method to get a pet to 25 (cant provide link as I need 8 posts)
Then, shame on me, i bought a few 25s of the AH, but that was no fun so I started doing my own leveling.
Now, all tamers are taken care of, and the Menagerie Dailies, while not trivial, are beatable.
Next on my list now is the 600 Pets collection, looooooong way to go.
But to answer your question, the guides here and on wowhead are generally great, though many times reliant on specific (rare) pets.
I generally go there for an idea, then search what pets I have with similar traits.
Most of the time the double counter pets will get you through anything (cant provide link as I need 8 posts)
Just search double counter pets in google.