Cocktail attire is all about wearing a suit....Black tie- means wearing a tuxedo...you don't have to wear the bow tie...go for a cool colorful tie and don't forget the cuff links - they add a unique touch.
Formal attire will range from cocktail dresses and dressy pantsuits to full length gowns. You will see a little of everything.

I tell people to dress as if you were a guest at a formal wedding, so a cocktail dress is fine. There is no difference in one formal dinner or the other although people tend to dress more formal for the Captain's night dinner (the first formal night) than for the second night which is the farewell dinner.

If you wear a nice pair of black or tan pants, you can wear a number of different things on top. For the winter months, go for a nice pair of wool slacks and for warmer months you can opt for thinner fabrics.

On top, you can wear a simple button down shirt that is a bit more relaxed that you would usually wear to work. A flannel shirt, when done right, can look casual and chic, yet still professional for work. Dress it up a bit with some nice black dress shoes and you'll be good to go! Add a blazer if you feel you look a bit too casual.

A sweater on top is also a nice look. Layer one over a button up to make it appropriate for work. A nice rich color (like navy blue or burgundy) would look great on you.

To make the suits you already wear look less stuffy, why not wear a t-shirt underneath? Make a solid one, again in a darker color. The result will be a youthful look that is also professional.

I think that jeans would work, but ONLY in a dark wash. Shirt-wise, if you're wearing jeans the top needs to be more formal. Go for a brighter colored button up shirt...light blue would be a good choice. You could also go for a dressier sweater. You don't have to stick with blues...go for a green or a nice burgundy color.

It's always better to be slightly over dressed than too casual. I would go for nice black pants and jacket. Find a unique shirt (can be a color) with cuff links (if you have it) - for this you can get away with not wearing a tie and you'll still look casual cool in a country club atmosphere!

And, the most important - have fun and be confident! It will make what you are wearing even better.

I always say, it's better to be a little dressier than too casual. Go for Dressy Casual (usually means no jeans or shorts). It's very similar to business casual, but a tad dressier. You could wear slacks (khaki) with a really cool French cuff shirt (make it a interesting print or stripes in unique colors).

Find some interesting cuff links - either go vintage or go new, either way, you're unique. I love this look because it shows that you took extra thought and it looks great.

I think since it sounds like the wedding is really casual, you can get away without wearing the jacket. Be sure to tuck in your shirt and get a cool belt! Pay attention to your shoes too. This look is casual "chic" look for sure and you'll fit in either way.

Look for clothes that fit your personality and that you will be comfortable in!