A "frog gig" (spear) is good, but here's a different way that a cousin taught me about 40 years ago (I was eight at the time, lest ye think I'm 102 years old :lol
:
Get a basic fishing pole and put a small panfish hook on the end of the line, nothing else.
"Bait" the hook with a small piece of red yarn, about 1.5-2 inches long. Yep, plain old red yarn... just set it on the point of the hook and let it dangle.
Keep it airborne and dry, and just dangle it in front of the frog's nose, and he will definitely hit the hook. Reel him in, repeat.
Last but not least, the state has laws about taking reptiles, so make sure it's legal to frog hunt in your area, and more importantly, make sure the above method I suggested is legal before you try it... nobody cared 40 years ago, maybe they do now.