EXS 24 Logic Sampler Users Group

I expect this has been covered before, if it has please be patient. I 
have recently converted some samples (bad akai i think) and the loops 
were really bad on some zones. Clicking on the "E" took me to the 
audio window which showed the loop points - but where to from there? 
Guess them? Maybe I am missing something fundamental, but some sample 
editors do a pretty good job of automating the looping. How do you 
guys do it please?