Planning - Budgets - Incidentals
Incidentals are a tough one to pre-budget for. For instance, you will have some extra (unforeseen) expenses if you break a shoelace, get gum stuck in your hair and need a haircut, or discover upon arrival that you completely forgot to pack underwear. Incidentals are generally minor expenses, unless you drop your suitcase in a canal or need a new camera after forgetting it on the metro. In any case, they are completely unbudget-able but should be budgeted for nonetheless. Confusing? To be safe, ensure that you have sufficient funds in the bank to cover any unforeseen incidents. If you are emptying your account to pay for the trip then any unexpected expenses will cause major stress, but hopefully that isn't the case for you.
Perhaps the only useful advice is hang on to your camera and make sure to pack underwear!
(And save a few euros for irresistably cute marzipan animals...)