A general learning problem

[lirongr]

Hello,
I am trying to find a good prediction model for a certain outcome on the basis of several variables. After taking a look at the data (plotting etc'...), I don't see any clear pattern. Does that mean that I cannot find a good predictor to my outcome? Is there a clever way to tell whether my outcome is predictable by my inputs or do I have to run different algorithms and see which one gives a good results?
Thank you,
Liron