Off the beaches for snook- During the day, anything white that doesnt make too much noise/vibration. If it's dark or low light, I typically throw black or black and chartreuse. Sight fishing is the name of the game. Look for a shadow, or maybe even a small puff of sand. That's all you get with them most times. If you are close enough to make out their whole body, it's over. At night, anything works as long as it's a black topwater. Same approach for Tarpon but they're likely to be out past casting distance. Every now and then you'll get one that comes in close.
In the back country, chartreuse/white or just chartreuse jerkbaits most of the time are my ticket. If it's super dirty I'll throw rootbeer with a chartreuse tail or just plain rootbeer. I've never had much success on anything else. A bunch of guys throw swimsuits on jig heads for them with great success, but I'm partial to the weedless approach, especially around mangroves. If all else fails, go with live pilchards (whitebait, scaled sardines, greenbacks- whatever they call them in that area. They're silver with a green back and are anywhere from an inch to 5 inches long. Hook them through the nose on a 1/0 or 2/0 circle hook)
I'm useless for targeting mackerel with any great consistency. I usually catch them in the surf when I cast too deep to catch a snook.