Let's look at a 1962 McCall's dress pattern I recently purchased:
Jackie Kennedy-inspired patterns must have sold really well in 1962! The illustrations are beautiful and give you a superficial idea of how the dress is constructed: bow collar, darted bodice, skirt variations. But it is the pattern description that really tells you what you need to know about this dress:
"Dress with dart fitted bodice and three-gore slim skirt, or four-gore skirt with unpressed pleats. Short set-in sleeves; two-piece collar crushed under applied bias bow at left front. Slim skirt has side front pleats, darts and low pleat at back. Slim dress has left side zipper placket. Opening in left side of full dress is fastened with zipper, hook and eye, and snaps."
Now that is a pattern description. It tells you absolutely everything you need to know, and gives you the information you need to determine whether this is something you want to or are able to make. You could go look in your sewing manual to see how complicated a two-piece collar is, or what on earth a gored-skirt is. The more patterns you read, and the more garments you make, you will be better versed in the terminology of pattern descriptions. This in turn will make you better equipped to make good pattern purchases.
Unfortunately, most contemporary patterns won't help you here. Take, for example, Burda Style #7063. The pattern envelope just says: "Blouse and dress; semi-fitted." Where are the details? How is this garment constructed? You won't find out unless you buy the pattern and read the step-by-step instructions. Even worse? The so-called detailed description in the online catalogue:
"Dress and blouse, almost a little frumpy & innocent. The loose-fit collar & smocked waist recalling the 50's give it its special charm. Delicate fabrics with fanciful prints underscore the style."
...frumpy and innocent?
....frumpy and innocent??
Oh, Burda Style. What have you come to?