If you drag the images manually to tweak things, you may like the Align button. Click the overlap between images and then click the Align button. Here I show how to adjust the seam with too - typically useful in the sky.
Compact cameras are very practical, but when shooting panoramas the auto exposure does not anticipate what you are up to. Here is a short clip which shows some of the exposure controls which allow you to adjust the images as you like. I show "Select All" in the video clip, but it is easier to hold down the shift key and click the images you wish to select. That way you can add or subtract exposure from several images at once.
If you have two images which are mismatched in exposure, the "Match Exposure" menu item will even out the differences. This may not be what you want and undo will revert the changes, and you can do it directly with the tools shown above.
Some places ask for 360 degree shots. With some discipline you can make 8-10 photos and get overlaps for a full panorama. A tripod is best, but you can do without as DoubleTake makes it simple to straighten the horizon. This 60 second movie is made with the 3 photos of Chambord Castle and shows how it works.
QTVR was once used a bit, but Apple has discontinued it in 2012 and it is no longer a part of QuickTime X (QuickTime 7 Player can play them). Notice how the horizon straightens when the mirrored image is moved, and how I zoom and scroll to the place where I wish the QuickTime VR movie should open. This panorama is cheating as the 3 images cover 180 degrees in reality, but it makes a shorter video. Toady you can save as a regular image which covers exactly 360 degrees.