Might be a bit of trial and error for you to get the best one that suits your tastes - have a look at
http://www.astray.com/recipes/?search=batter and scroll to fish batter .
Beer batters tend to be a bit lighter so crispier - couple of options on the link as well.
Make sure the oil is really hot as well before you put anything in to cook, - do not over-crowd the fryer for both safety reasons and to make sure that the oil is not simply absorbed by the fish.
If you are cooking a couple of portions, better to do it one at a time and let the oil always return to temperature for a proper result before putting the next portion in.