Summarize the following:
Baccarat strives to be at the cutting edge of style, so you can often date pieces based on the design. Read old catalogs and look at pictures of Baccarat crystal online to familiarize yourself with the work.  Cube shapes were popular in the 1920s and 1950s, when Art Nouveau styles were popular.  Venetian glass had a heavy influence on styles manufactured in the 1960s. Due to subtle differences in manufacturing and the intricate nature of crystal, it can be hard to compare your piece to a photograph of a similar style. Line drawings, like those used in early catalogs, can help you determine the date of your piece with more accuracy. Baccarat has employed different crystal designers through the years, each of whom brings their unique style to Baccarat crystal. By familiarizing yourself with these designers and their art, you will be able to identify their work when you see it. For instance, if you are familiar with the Ballon pattern from 1916, which features trellis-like embellishments, you may be able to identify a piece as Baccarat even if there are no Baccarat markings. Reproduction Baccarats are common, but due to the replication process, original Baccarat crystal will be significantly heavier than an imitation. If you're still not sure about the origin of your piece, contact a Baccarat representative or visit a Baccarat dealer near you.  To find the closest Baccarat dealer, visit http://store.baccarat.com/. You could also look online to find antique dealers who specialize in glass art and Baccarat crystal.

Summary:
Study collectors' websites and catalogs to identify Baccarat styles. Use line drawings in old catalogs to identify antique pieces. Study the styles of the designers who worked for Baccarat. Check the weight of a piece. Bring your item to a Baccarat store or contact an expert online.