I keep it simple, I use a store bought flower called FRY CRISP. I use a full body beer I preferr OLD MILWUAKEE because it's cheap.
I mix the flour and beer together with an electric mixer. beer at room temp mixes the best. And I like the batter water thin running off the fish. I don't like thick batter that is oil soaked. I like to get my oil to 350-375 and start with 1 piece to test. Then I only put in 3-4 pcs at a time ALWAYS keep an eye on the oil temp do not let it get below 325. Fry untill you get the golden brown color. I use clear canola oil. It's expensive but I like it better than anything i have used. place them on a plate with a paper towle on it. You can use a turkey fryer a pan cast iron pot works good.
I have a cajun fryer made by rv works in louisiana Made in the USA. I am not a dealer but it works the best. I use the same oil for 2 summers of cooking. Because of the way the cooker is made. Thats why I go by cajun fryer here on CDC its an inside joke from crappie camp 2010 My fryer and evil twin Mickey saved the day. but thats a hole nother story. Any questions just ask. I have been doing it for years. We fry at are fire station twice a year as a fund raiser.