There may be few experiences as exciting in fishing, as that of a large fish exploding on a topwater fishing lure. My favorite moment was actually a very large Striped Bass I ended up not catching. I can vividly remember the sight of an enormous tail waving above the surface, as this trophy Striper ground the lure on the bottom until the line broke. I suppose fish don't get that large without some smarts.
There are many fishing conditions where fishing a topwater fishing lure is almost essential, due to a lack of water, difficult structure, or perhaps you're just not sure what you're facing, so a topwater lure is a good way to start.
When using a topwater fishing lure, you're generally doing one of two things. First, you're simulating a fish food which lives on the surface, such as a frog. In such a presentation, you are simulating the hopping of the food source in a natural fashion. For example, when fishing a popper near lily pads, rest the popper on the edge of the pad, before taking it over the next open area.
The second type of bait you are simulating, is a baitfish which is injured and dying, and which is on or near the surface, and moving in a very erratic fashion. In such a presentation, again, you wish to break up the motion, because as you've seen, a dying fish does not swim leisurely and smoothly in one direction.
However when trying to immitate a bait on the surface, you may wish to wildly vary the speed. A slow retrieve, encourages a hit, as the fish thinks it has not been spotted. Whereas a fast retrive also can trigger a strike, as the fish believes its next meal is escaping.
The so called "walk the dog" motion is used for many topwater fishing lures which are cigar shaped. The retrieve on these lures relies on the fisherman twitching the line and letting it go slack as the bait skids to one side, repeating the twitch to move it to the other side. This simulates a dying baitfish on the surface. Use light lines tied directly to the bait, to permit the lure to swing from side to side easily.
In general, the murkier the water, or the choppier the water, the more noise you need to employ to provide that easy target to your fish.
So called jerkbaits are again used to simulate a dying baitfish. You want to rip the baits, often letting them go under the water a foot or two, before coming back to the surface. Rip and pause, rip and pause. Often giving just a slight twitch at the end of a pause will cause the suspended fish to nail it.
Although topwater lures can be used in a variety of conditions, I need to say that I am partial to those periods of dead calm, when it is not only quite easy to fish a topwater lure without wave or drift action to put a droop into the line, it's also that calm which accentuates the startle of the fish hammering the bait. After all, fishing is not so much about catching the fish, as the experience itself.