When selecting shrimp, look for those that are moist and firm, have translucent flesh, and smell fresh.
Avoid those that have an ammonia smell and blackened edges or spots on the shells.
Since most of the shrimp available today has been previously frozen, always check it to see if thawed shrimp is firm and shiny. If purchased frozen, make sure it is frozen solidly and has no signs of freezer burn. That frozen shrimp overnight in the refrigerator, or place under cold running water.