Especially when boozing. Get your friends' emails and keep in touch. Ask your relatives to send you any amenities if you are in a spot long term. Eat from a grocery store to save cash. Get a group and RV, it is cheaper and more flexible than the train.
Museums often have free or reduced admission on certain days.
Beware of pickpockets and con artists. Look at it as a game and necessary in order to not offend the seller. Mother always said, If it seems to good to be true, it is. Drink bottled water in 3rd world countries. When walking through the cities of Europe, look up.