The only thing I've figured out about topwater is I don't have a clue when it will work, and when it won't. The lakes I fish have little to no vegetation. I rarely see or hear any frogs. (in my mind that's due to the lack of vegetation). Most years the top water action heats up when bugs get active and start falling into the water. Find someone mowing grass near the lake, throw something topwater in that direction.
The strangest top water experience I've ever had was January of this year. I was at a lake I don't fish much. I caught 3 or 4 early (for January) relatively deep on an A-rig. Then I lost them. I couldn't find the bass. It was a sunny winter day. The water was fairly clear and calm. I was skipping a dock and got hung on an underwater rope. When I went to get my lure loose I could see bass in almost no water, facing the bank. I cast a t-rig onto the bank, and crawled it into the water. They ignored it. Again, I could see these bass in the water, not on sonar. I threw a jig onto the bank, and crawled it into the water, still ignored. I tried both of these several casts, and at a couple different locations. Finally, laughing at myself the entire time I tied on a Devils Horse. (top water). I didn't cast it onto the bank, but right to the edge of the water.....18 inches or so in front of a bass. EXPLOSION!!!!!! The bass was almost out of the water getting the bait. I didn't even move the lure, and barely had my reel locked. I caught several more the same way that day. The water temperature was in the upper 40's. I figured the bass were soaking up the warm Sun. Was there something coming down the bank (or out of the ground) into the water for them to eat?
I wasted a bunch of topwater casts in COLD water after that. The only other topwater bites I had until April or so were one Bass and a 13 pound Catfish over cane piles. (I thought the Cat was a hawg for a while)