I always click all 60 after all its free and a chance of winning a cash prize, I have won $10.90 in 18 months (14 as a premium member), although I consider this low it's about right in a game of chance where upto 5 million members are involved.
All I can say is the more times you click each day, better the odds on you winning, I must say you are very unlucky not winning anything in that space of time, I think the longest I have gone without a win is about a month..
Edit: Not trying to rub salt into your wounds but since i posted this an hour or two ago i have won three times on ClixGrid, twice i won 5 extra chances and the third time i won 50c..