A lot of people make digital posters announcing art exhibitions. These self-contained nuggets are great, because they can easily be re-posted all over the place to promote the show (which is presumably the goal).
Out of the five Ws (who, what, why, when, where), the most common mistake seems to be incomplete coverage of "where". It’s easy to lose sight of one very important fact: when you post something online, you’re talking to the whole world. It may seem perfectly obvious to you that Flemmingtonville is the next town over, but unless you put it on the flyer, nobody looking at it knows what country you’re talking about, let alone which state or province.
Even the names of well-known places can’t be considered definitive. In the US alone, there are Parises in Arkansas, Idaho, Illinois, Kentucky, Michigan, Mississippi, Missouri, Ohio, Tennessee, Texas; Berlins in Connecticut, Maryland, New Jersey, New Hampshire, Massachusetts, New York, North Dakota, Ohio, Pennsylvania, and Wisconsin; Londons in Alabama, Arkansas, California, Indiana, Kentucky, Michigan, Mississippi, Missouri, Ohio, Texas, Wisconsin…
No matter how clear it seems to you on its own, I suggest fully qualifying the location with street address, city, state/province, and country.
If you want to go the extra mile, I suggest including a bit of text that repeats the name(s) of the artist(s), linked to their web sites. This helps everybody: it helps your potential audience see more work by the exhibitor(s) and hopefully gets them more interested in coming and buying work, it helps the people you want to re-post the info by giving them an easily copy-and-pastable chunk of HTML, and it helps the artists by providing more eyeballs for their work (and increasing their search engine rankings).
They seem like little things, but they can easily be the difference between "hey let’s go!" and "WTF".