MADCAP HORSE
For some reason, this just popped into my head today. It's a mnemonic I learned for tree and shrub identification: MADCAP HORSE. It is used to help you remember which trees and shrubs have opposite leaves. It works here in NJ at least.
Maples
Ashes
Dogwoods
CAPrifoliaceae - viburnums and honeysuckles*
HORSE Chestnut
*I think viburnums are now in the family Adoxaceae, so this may be a bit confusing
I'm sure there may be exceptions to this mnemonic, but it's worked for me.