When you are in the loop screen;
aproximate where you want the loop
Zoom in fully so you see something like this
with fixSize on shuttle up and down through the wave until you see a simila curve in both the 'eol' and 'sol' windows. - they might be a fair bit apart, mind.
turn off fix size, the move either the Start or End position to the similar bit of the wave curve.
make sure that the curve meets in the centre line, misalignment here is what causes the clicks.
Finally turn on fixSize so you can shuttle up and down the wave to check that the curve looks right (It should look like there is no seam in the middle)
Now you should Audition the sound to hear how the loop sounds - it shouldn't click but it might sound a bit robotic if the loop is too short or the pitch varies. About 1sec of continous pitch/volume is enough to trick the brain into thinking its natural IMO.
E-mu has a really good system for loop matching, if not one of the best. Even if I have been setting up a loop for the PC I have edited on the e-mu as it is so quick. I use wavelab less since I have had the sampler!