Help clear the mess up when the party finishes.
Write more than "Happy Birthday" in a birthday card. Think about the recipient and include a personal message.
Offer to water plants, take the rubbish out or feed pets for someone who is going on holiday. If you see flowers wilting in public areas, water them too.
If you open the free hotel toiletries but don't finish them, give them out to the homeless instead of throwing them away.
When you go somewhere to get or do something, ask the people around you if you can pick up anything they need.
If you have a bottle of perfume you don't like, leave it in a public bathroom for someone else to use.