In general, most sushis are safe to eat. Although, there are some precautions that you must know before consuming raw fish. Some seafood contains levels of mercury. The FDA recommends that certain type of people should avoid the consumption of raw fish. These individuals includes: pregnant women, women who are nursing, older adults, individuals with weak immune systems, low stomach acidity, and allergic reaction to shellfish. Lastly, you want to be sure that it is a reputable sushi establishment. Whenever I go to a sushi restaurant, I usually pop my phone out and do a quick Yelp review. Many users will post their experience. Read through a few reviews and then decide.
One helpful hint, if you're eating raw fish, it may be a benefit to add a little wasabi and ginger. I heard that wasabi may help kill any bacteria.