A baguette:   First, make sure it's fresh from the day. Prefer to buy bread directly from a bakery rather than from a reseller, because bakeries will usually clearly mark day-old bread. The crust should be crunchy and brittle, not soft. The color should be a light golden brown. The packaging, if any, should be made of paper and let the baguette breathe; anything else will cause the baguette to be soft and chewy instead of crunchy. If ingredients are listed, they should consist only of flour, yeast, salt and water.

A pastry:   First, make sure it's fresh from the day. While most pastries can last 2-3 days, their taste and texture steadily decline during that time. Most pastry shops will clearly mark day old pastries, but resellers don't usually do that. Pastries that are day-old or more have a drier, more tired look. Second, most of the time, you can trust that the taste of the pastry will match its looks; pastry chefs that can make great tasting cakes also have the skills to make them beautiful, so a good tip is to prefer stores that make good looking pastries.

Some chocolates:   There are few rules regarding buying chocolates. One is to avoid dull looking chocolates, as this may indicate they are old (though still edible). Chocolates can be kept anywhere from a couple of weeks to a few months, depending on the centers they contain and the preservatives that were used. As a rule, the shorter the life of a chocolate, the fresher it will be and the least preservatives it will contain; chocolates from larger chains are often made to have a long shelf life. Passed that, the main factor is of course your own taste; you can always buy just a couple of chocolates when you visit a new store, and return to buy more later if you liked them.