The best way to prepare for your trip is by booking on American travel sites because they stand behind their promise. If you live outside of the USA use your local travel agencies that are registered in your country, offer warranty and have a good customer satisfaction.
So you booked a room and arrived. The shower head is missing and there is no hot water. There is mold growing in the bathroom, water running in the toilet. You have an ocean view room but can’t see the water because of the dirty windows and spiderwebs. Plaster or tiles are coming off, the smoke detector start beeping at 3 AM because the battery is dying. You are in the mountains in the middle of the winter and heat is so weak your mucus could freeze to your face. This passed August on the Mediterranean in one my hotels there was no AC which was hard to bear; we opened the windows but the passing trains were pretty disturbing until about midnight. You book a nice resort overseas with a tropical pool and a swim-up bar but the pool is closed for either maintenance or for the season and green algae is growing int it.
What if you get awaken at 2 AM because the front desk called your room by mistake? There are people heavily partying in the room next to you, making noise even on the hallway, slamming doors. Does any of it sound familiar? For me it is all of the above, I have seen it all in my 25 years of traveling but instead of putting up with it, I opened my mouth.
Simply go the front desk and complain, hopefully they will either call for maintenance or transfer you to another room (in those cases they normally upgrade you) or give you a discount from your room rate when you check out, unless you prepaid it. One resort threw in free breakfasts, internet and valet parking for the remaining days of my vacation. If the problem persists then you gotta complain to your travel agency when you return; just document the case by taking pictures, perhaps the names you speak with at the hotel.
As mentioned above, travel agencies protect customers so if you could not resolve the problem directly with the hotel, they will help you, you can expect either a partial refund or a future travel coupon anywhere between $25 and $200, depending on how serious the violation was.
SPEAK UP, you have rights as a customer, even overseas!