Jean,
Widescreen can seem awfully different at first. After you've done a few, it will be no big deal.
If your camera is not a natural widescreen, it will letterbox your image in your LCD or viewfinder. This means you'll have a smaller viewing area and focus/exposure/etc. may be more difficult to ascertain. Thus a monitor or magnifying glass may be something to consider.
I've seen many people get thrown off with widescreen and they appear to create a 4:3 frame in their minds, and use only the right (or left) side of the screen. Be sure you use the entire frame and apply your normal "rule of thirds" for subject positioning - your "tic-tac-toe" figure will be stretched a bit, but the rules still apply.
Widescreen is best for some types of scenes and standard seems to work best for others. Be sure and keep your screen format in mind and get lots of those shot types that show the format at its best.