The trick about PAs is to make them interesting and you will get the attention of the punters. I have on occasions been impressed with PAs both from pilots and F/As. Unfortunately, not many have that special gift to make such PAs. This is by no means criticism since that is not what you're there for. A few tips:
If you are going to introduce yourself and the crew then don't rush and/or mumble your and their names.
Don't give the weather at destination before departure as it will invariably have changed by the time you get there!
Make sure that PAs can be heard on your a/c (you'd be surprised how often the pax can't hear what you are saying because of poor equipment.