Theres no time when it comes on investment when you want to invest you don't need to pick a date or time when you want to invest if you really want to then invest if you don't want then leave the investment site alone that's it 
it likes your just stocking your bitcoin from there but to be honey it is too risk they're promising you to get good income when you invest but they like fooling you and getting your money = scam
it likes your just stocking your bitcoin from there but to be honey it is too risk they're promising you to get good income when you invest but they like fooling you and getting your money = scamFirst of all - great punctuation.
Getting back to the discussion at hand, I think that you just have to follow the trend that the bitcoin is having, see moments in time when fluctuations are not too far apart and buy when it's a little low, then sell when it goes up a bit.
I think a bit of common sense goes a long way. And if you make 30-50$ on a transaction, then I think that is a good starting point.