So I've been constantly berated for my team choice in HeartGold and I feel quite proud of my "little engines that could" today.
I entered the battle against Whitney with a Croconaw, a Flaaffy, an Ivysaur, and a Togepi. I didn't have much of a strategy, but when the battle started, I instantly paralyzed her Clefairy and then took him down in about three ThunderShocks.
So I went against Miltank next, obviously. Paralyzed him right away, but it had a berry that healed it, so Flaaffy paralyzed again and ThunderShocked a few times, but in the end, it took out my Flaaffy. Then Ivysaur came out, because I wasn't sure if Whitney could heal Paralysis and Ivysaur has Sleep Powder, so that'd be my next move. But I ended up Leech Seeding it and Razor Blading a lot, but that stupid Milk Drink move kept healing it. So thanks to the advice of a good friend, I just let it whittle away at its Milk Drink PP until it practically ran out.
It kept using Attract, so I kept swapping between Croconaw and Ivysaur, whittling away constantly at its HP. Croconaw would Bite it and cause it to flinch, stopping it from using Milk Drink if it had any left. Then I pulled out my Togepi for a final blow, since we neared the end (Whitney also used a Super Potion at some point) and so I used Metronome and Togepi landed on some bird move that repeatedly attacked Miltank. Miltank managed to land a final Stomp in, but the Leech Seed scraped away that last bit of HP, ending the battle about 8 minutes after it began.
So I'm proud of my team. They don't suck, despite what I've been told frequently. :>