It all depends on the size and style of the soft Swimbait I'm using....The one constant that I have found to be the most productive however is a slow, slow, slow retrieve...
Work the bait beside the boat a bit and watch the action as you're retrieving the lure, as well as watching it to establish its sink rate...
Look for what appears to be the most lifelike action as you try different speeds...This will vary slightly depending on line weight, hook size, body style and using a weighted or non-weighted hook...Most people, myself included, have a tendency to work these baits much too fast...
Every so often, kill the retrieve and let the bait fall back on a semi-slack line...Many times you will get your hit as you re-start the retrieve...You will also solicit strikes if you "rip" the bait every now and then, and then let it drop on semi-slack, or slack line...