No 1 Tip = KNOW prices and process. As others have said act like this is your twentieth time in LOS.
No 2 TIP= Let them pick you. Don't always go with most beautiful - look for attitude, eagerness. Let them earn your $$$$. My MO is show them you are not a scrooge by buying the first drink, then let them earn the rest. Reward "positive " behaviour.
No 3 Tip = Must be prepared to walk away. YOU are always one who is controlling the situation. Don't let them control the situation.
No 4 Tip = Only carry / have accessible what you are prepared to loose. Don't get slack with security of money & valuables.
No. 5 Tip = We all have made mistakes, been scammed at least once, laugh it off because of tip 4.
No 6 Tip = You're on holiday = ENJOY ENJOY ENJOY = make it a trip you will remember forever!!!!!!!