No special trick.....ask the locals where they are. The smaller mesh will catch you more, as they are not as large as the spotted ones. Used to catch them by the bucket full in water no more than 35 feet with homemade flat traps. Had to pull fast to get the buggers to stick, but the fishing was fast and efficient. Flat traps are a waste of time if you plan on setting them and going fishing though. The shrimp often times come in shallow at night.
The fresh tails are good summer run bait, too.