Hey everyone, 
I am quite at a loss and I am not sure what to do know. Here is why:
I've recently tested two LP's:
LP_1 had a long copy (a salesy one, in which I explicitly was promoting the product); LP_2 had a much shorter copy (around 500 words) and was more of a review page (which was allegedly written by a guy who used this product) with very little marketing.
LP_1 had a click-through rate of 23% (23 out of 100 clicked on the CPA button which lead them straight to the order form), 0 sales.
LP_2 had a click-through rate of 36% (36 out of 100 clicked on the CPA button which lead them to the merchant's LP), 1 sale.
Now I am not sure what I should do next. I have suspicions that this single sale was random and by luck.
Shold I test:
1) LP_2 to find out if my suspisions are justified
or
2) LP_1 (adding some new elements to it)
or
3) LP_3
P.S. I am promoting a fitness product using Clickbank.
Thank you very much in advance.
Get more stats on both LPs. 100 clicks to a lander isn't enough. After you've got a winner between these two, test a totally different style lander than the previous two (with similar copy/headline) then find a winner and start optimizing it. Make sure you test other offers as well in case they convert better.
PS is your username a reference to anything in particular?? 
Thank you very much for your advice. Will do that and tell what hapenned. 
Haha, when I was younger I used to play World of Warcraft and there was a goblin NPC whose name was Ziz Fizziks. He would say amusing things and since I found that pretty entertaining I decided to adopt this name for fun and to bring back some good memories.
Great advice from Doryphoros.
100 clicks to a lander is nowhere near enough information to make an educated decision.
Always be testing. Even when you find a winner...you should always be testing, revising, and optimizing.
ah ok haha, I thought with a name like zizz and promoting a fitness product your name was a reference to fawkin zyzz brah! 
Hahaha, now I'm definitely mirin', didn't realize there could also be a Zyzz reference. 
Thank you very much for your recommendation, Miket. It's very useful because quite often I forget that I should always be optimizing.