Learning about the sweetness levels.

If a bottle says Trocken on the label it's going to be a dry wine, Trocken is German for dry. Halb-trocken, or less commonly Feinherb, will mean that the wine is half dry, it will probably still seem dry to someone looking for a sweet wine though.

The German QmP ripeness scale begins with the least ripe grapes, which will generally translate into the least sweet wine. These classifications only reflect the minimum level of sweetness so any category can be decalssified into a lower category.
A rough rule of thumb for reading ripeness levels.

    * Kabinett - lightly sweet
    * Spatlese - noticeably sweet
    * Auslese - decidedly sweet
    * and then the dessert level
    * Beerenauslese - richly sweet
    * Trockenbeerenauslese -intensely sweet and honied
    * Eiswein - Icewine - a rare treat, sweet yet bright

You can find something labeled as Spatlese Feinherb for example but as a general rule: Auslese is sweeter than Spatlese, and Spatlese is sweeter than Kabinett.

There is another group of lower priced wines that are generally labeled with proprietary names, "L" and "Dragonstone" come to mind. These so called Qba wines tend to fall about midway between Kabinett and Spatlese sweetness.

One way to further narrow your search is by checking the alcoholic content of the wine. The higher the alcohol, the less sugar remained unfermented, so the drier the finished wine.