#1 So many People, so many Minds
The first thing to bear in mind is your standard vs. standard of people from other countries. I don't like stereotypes. I really don't. However, person from Germany or US will have different level of standard for cleanliness or atmosphere than Asian or East European (I'm East European myself so I know what I'm talking about). The same applies to person from city vs. person from rural areas.
What to do about it: Read reviews from people you can identify with (based on age, country etc.)
#2 Read the best and the worst reviews first
You want to know what exactly was so amazing or, what was so bad about the hotel/restaurant. If someone loves the place, he/she will more likely state the reason why and the same applies to haters (who are usually the most loud). The more specific, the better. "The best hotel ever" or "Horrible services" are too vague and probably fake. Also, look at more websites with rating of the hotel and don't be afraid to message people who wrote reviews and ask them for details. Maybe they wrote hateful reviews in rage the very first day in hotel, but now they can write you more details with cool head.
#3 Mighty Google knows everything
In case you are not sure about the safety of location or how far the hotel really is from the beach, why don't you look it up at Google Maps, or even better - at Google Streetview? Check out the area - is it close to big road or shopping center? Is it too far from any buildings? Are there slums too close? Compare your findings with reviews and hotel description. The more accurate the better.
Have you ever been disappointed in hotel or restaurant despite it's great rating online? Do you have any rules when looking for accommodation?