This is by no means the definitive guide to good sushi, but it is a basic guide for loving your sushi the way it needs to be loved (and not getting all hung up on that ratchet Jessica Albacore roll).
The first challenge is to get out of your head what some friend (re-consider your friendship with this person), media outlet (most are just collecting a pay check), or a Yelp Elite writes:
“Like OMG, it’s so fresh, it melts in your mouth.” – Yelp Eliter
– Every Yelp Elite

- 1). “like OMG, it’s so fresh, it melts in your mouth.”
- 2). “the rice is not supposed to fall apart because how else can I eat it after chill’n in my soy sauce!?”
- 3). “I only like big slabs of fish because I don’t eat the rice.”
After you have moved on from people trying to steer you wrong, you are ready to look out for the subtle details that matter.
NIGIRI SUSHI RICE (Shari/Gohan)
The most important aspect of sushi is the rice (80%). Yea, the stuff isn’t there just to soak up the soy sauce.

The type of rice, grain size, how old the rice is because younger rice is more moist while older rice needs you to lower that basket of lotion down to it (also absorbs the shari su more effectively), how it is washed/rinsed because you do not want broken grains, to the cooking times (cooked el dente) all play into nigiri sushi as much as the topping does.
When being served, the sushi shari (rice) should ideally be served at body temperature unless you are dead, or you are buying your sushi from a gas station.
As for the flavor, yea, sushi rice is flavored with su which can vary, but most restaurants will use a red vinegar, or a mixture of vinegars and salt while some will also add sugar.
NIGIRI SUSHI TOPPINGS (neta)
All sorts of toppings can be used from raw to cooked, but the topping should be paired with the sushi rice to create the perfect balance (like with me and you, if you are a hot female model reading this).

Like any meat, produce, or ingredient, they all have a particular way that they need to be butchered/slaughtered (ikejime is the process used for fish). The specialized techniques maximize the ingredients quality and flavor by also dictating how and when the ingredients are cut and at what temperature they are served at.
There are a number of fish that are best when absolutely fresh (hikarimono to shellfish), but not all fish are best when pulled right out of the ocean (maguro to a number of shiromi/white fish: halibut, seabream, to snapper). The whole “melt in your mouth” thing is not due to it being strictly fresh.
Like with beef to chicken, dry-aging and a number of techniques are utilized to make the flesh softer or to maximize flavors such as aging, marinating in vinegar, salts, to soy sauce (shoyu), or utilizing konbu to compliment or maximize the umami of an ingredient…. mmmh, glutamates.
NIGIRI SUSHI PREPARATION (nigiri to gunkan)
Knowing how to form a proper nigirizushi of rice and topping is key to creating a perfect bite of happiness (it’s great when you can’t get it through food).

Properly prepared or formed sushi has to compliment the neta. When you eat it, the rice should break apart and blend well with the topping that has been brought to room temperature. When the rice and topping are both done correctly, they blend together as one harmonious bite.
With gunkan, the nori should be nice and crispy to provide the perfect contrast to the rice.
Appreciate the Details Foo
Sushi, like a lot of Japanese food is an appreciation of the ingredients natural flavors and there’s an appreciation to its simplicity, but that’s why a lot of others look over those details in lieu of fluff: gold flake, foam, flowers, fancy plating, etc. (the Jersey Shore of sushi).
Hopefully this helps deepen your appreciation of sushi, but if not, you still got your Jessica Albacore roll because she’s only a side chick to me.
*thanks BB for ratchet.