Before anything else, pat the shrimp between several layers of paper towels. Pro Tip: Moisture is the enemy of a crisp crust. If the shrimp are damp, the flour will turn into a gummy paste rather than a light breading.
Combine the flour, seasoned salt, and pepper in a large gallon-sized Ziploc bag. Shake it vigorously to aerate the flour. This "cloud" of flour ensures a more even, thinner coating on the shrimp.
Add only half the shrimp to the bag at a time. Shake until fully coated. By working in smaller batches, you prevent the shrimp from sticking together and ensure every curve of the seafood is covered.
Heat the oil in a deep skillet over medium-high heat. To test if it's ready, drop a pinch of flour into the oil; if it sizzles and disappears immediately, you’ve reached the "shimmer" stage.
Carefully drop the shrimp into the oil. Fry for only 3–5 minutes. Crucial: Watch for the shrimp to turn opaque and the coating to reach a pale golden brown. Overcooked shrimp become rubbery and "bounce."
Instead of piling the shrimp directly on top of each other, spread them out in a single layer on a paper towel-lined plate. This prevents steam from being trapped between the shrimp, which would soften the crust.
Let the shrimp sit for 60 seconds before serving. This allows the internal heat to finish the centers while the exterior crisps up.