Tip #1: Just because you don't eat fish, does not mean you should steer clear of sushi. There are several yummy and healthy rolls for vegetarians including rolls that contain *only* avocado, cucumber, carrots, or any combination of the three. These rolls are tasty, filling, and make a great, low-calorie (2-4 WW points), crunchy, on-the-go lunch or snack. I highly suggest trying a vegetarian roll if you haven't already. You can buy these rolls at places like Whole Foods (there is no need to go to a sushi bar to get high quality fish, since there is no fish in this sushi).
Tip #2: Try to find sushi that is made with brown rice. The difference in taste is minimal (you might even like the brown rice taste better, I know I do), and brown rice has more fiber, making the sushi even better for you.
Tip #3: People often ask me how many calories are in a piece of sushi. It is actually easier to calculate by the roll, since different sushi chefs cut different sizes of rolls (for instance, some rolls have 6 pieces, some have 8). Here are a few resources for looking up calories and points for sushi: Calorie King, Peer Trainer, Sushifaq (contains WW points!). Figure out which rolls you want to eat before you go out, and that way you'll be set up for success.
Tip #4: Rolls with fried fish in them are not great choices (watch out for tempura or spider). If you are craving something fried or crazy, try just having a piece or two (share the rest with your friends). In most cases, if you want something super yummy, it is smarter to order a "spicy" roll than a tempura or a spider roll.
Tip #5: Rolls with one piece of fish (like tekka maki, sake maki, or california roll) or fresh fish slices without a roll (sashimi) tend to be easier to calculate calories/points for than rolls that have many different fish or ingredients in them.
Tip #6: If you are watching your sodium intake, try eating rice vinegar instead of soy sauce. However, while rice vinegar generally has less sodium than low-sodium soy sauce, it still has a fair amount of sodium in it, but what makes it different is that a little goes a long way. Another option (again, still contains sodium, just less) is to put a small piece of ginger on each piece of sushi.
Tip #7: If you are eating at a Japanese restaurant, miso soup is a great choice to accompany your sushi. It is very low in calorie, and only .5 WW points.
Enjoy your sushi!
Note: Picture by BITTER on Flickr.