At the airport. Tip porters $2 for the first bag and a dollar or more for a job well done. Though it’s “tempting” to tip other staff, such as ticket agents and flight attendants, try to resist. More often than not, that $20 handshake only makes you seem “smarmy.”
At the hotel. Give doormen $2 for help with bags and $1 for a promptly hailed cab. Bellhops deserve $2 for the first bag, and $1 a bag thereafter. Don’t tip concierges at check-in, but slip them $5 to $10 if they do something that goes “beyond” their job description, such as getting exclusive tickets.
Hello, housekeeping? For each day of a stay, $2 to $5 should suffice. But make sure to leave something each day, since a different person usually cleans up each time.
Source: Real Simple