Sure, there are thousands of articles out there, that will give you advice on what to wear to work - but what about everywhere else?
If you are as fashion clueless as I am - but can grasp enough to feel awkward when over or under dressed, then this is for you - and ME!
A Baptism or Christening:
Or any other religious ceremony
A pretty daytime dress or feminine jacket-and-skirt (or pant) combo is the safest bet. If the event is held in a church (or other religious building) you should keep it modest - nothing low cut, short, or revealing. Although some dress codes are very relaxed for their regular service, because it is a special ceremony, it is expected to be more formal.
Another tell tale sign of what is expected, is the order of events. For example, if attending a Bar Mitzvah, if the party afterward is helding immediately, a cocktail dress would be perfect - but cover up with a wrap or jacket while at the temple.
A Business Dinner ot Work Holiday Party:
A simple little black dress (or any colour) and adorned with larger jewelry or colourful heels you wouldn't normally wear to work, would be considered perfect.
A Funeral or Wake:
A suit (skirt or pant) or a knee length dress with a cardigan would be best. It isn't so much about the clothes you are wearing - as long as they convey the somberness of the event. Tone downed clothing in darker colours - it doesn't have to be black - are the best choice. Avoid loud patterns and flashy pieces. Jewelry should also be quiet and classic - just keep it simple.
A Wedding:
What to wear to weddings these days, all depends on the wedding!
Black Tie: A mid calf to floor length dress and heels. Think Old Hollywood glamour - not Disney Princess! Add classic style jewelry.
Black Tie Optional: Same as a Black Tie - except a knee length cocktail dress would also be appropriate. Your jewelry choices are a little more liberal - go for sparkle!
Cocktail or Semi-Formal: A colourful, but still sophisticated, dress, knee to mid-calf length. You can also opt for a formal dress pants and a sophisticated blouse.
Beach Wedding: A long, flowy sundress or maxi dress would be perfect - especially in pastels or tropical colours. Flats or fancy sandals would be the better choice.
Outdoors: A colourful dress and bold jewelry would be a perfect fit. Avoid heels though, you'll only sink in the grass. Wedges or flats would be the best choice.
City Hall: A dress would be nice, but a nice skirt or pant with a pretty blouse would also work well. What is happening after the ceremony should tell you how to dress - lunch at a pub? Dinner at a high end restaurant? Party at their place?
And if you are still in doubt - do a little research. I'm sure a google image search of the location or the theme will give you more ideas as to what is expected.