Will repeat what the others said and add some.
-- better to use focal lengths of at least
50 mm ... wide angles cause more edge distortion and make stitching more difficult
-- more shots at longer focal length are better than few at a wide angle
-- shoot with lots of overlap between frames...
-- M mode is the way to go...take 2 or 3 shots to determine a reasonable exposure...if you use A mode there will be slight variations in sky exposures as you shoot across the scene...
-- portrait (as Kurt noted) is often preferred..for one thing you get more sky and land in the shot which is important when shooting at say 60 mm FL.
-- it is common to use a polarizer on sunny days to enhance the sky...the maximum effect happens at 90° to the sun....as you pan across the sky the effect of the polarizer will vary ... meaning that a perfectly uniform blue sky will vary in color value.... you can see this in the image below. The left is at about (say) 30° to the sun off to the left...and the darker center is 90° to the sun....just be aware of this and you may choose to shoot with no polarizer.
-- I routinely do not shoot with a tripod..but you
The pano capabilities of PS Elements are really quite amazing....usually impossible to tell images are stitched....if and when the boats and dog sleds get an A77 into Sector 17, I will also buy the new 16-50 SSM lens for it. I have a plan for a killer pano next spring or summer...we have a bare wall in the dining area...it needs a 6-ft pano of my favorite mountain range.
It is gonna be sweet. Right? Effects of polarizer on sky color value