Bart:

early morning and afternoon when it cools down a bit
technique is simple, just cast your lure out and reel it back in. Watch for submerged tree branches or other floating debris
adjust your speed until you get the best catch rate
on second thought, you should try plastic worms, works better imho

Nick:

I usually have the best time fishing topwater right as the sun comes up. The water is cooler and the sun hasn’t been able to heat it up yet, so the fish won’t be driven to the cooler, deeper water and more willing to feed on top. What kind of topwater lure are you planning on using? If it is a popper, give it a short jerk, so that it gurgles the water (I like to make sure it dives under just a bit), and reel up the slack and repeat. For something like a Zara Spook, an excellent topwater lure, you have to learn to “walk the dog” by twitching the slacked line to make it glide from side to side.