I need a riesling to live! Yeah that's pretty corny, I know. Something else I know is that riesling is one of the greatest wine grapes, capable of making stunningly complex wines in a variety of styles. That's a strength that you can use to your advantage, few wines go as well with food across the entire spectrum. I love fresh corn on the cob, but unfortunately it's a difficult match for wines and yet one of my favorite things to drink with it is a riesling with some sweetness. Please don't think that partly sweet, off-dry wines are of lesser quality than dry wines. I'm not going to entertain such a silly notion, I'll only say that just because you ferment all the sugar out of something doesn't mean it's better than something else.
The thing to understand about riesling is how the balance works between acidity and sugar, and the obvious analogy is lemonade. Lemon juice by itself is extremely tart and unpalatable, you add sweetness in the form of sugar (and water) to balance the acidity and hence, lemonade! The thing is, everybody's different in how they like their lemonade. Some people want it really sweet while others like it really tart. Riesling is a grape that has a high level of acidity which is balanced by the natural fruity sweetness of the grapes. When a winemaker makes the wine, the fermentation starts to convert the sugar into alcohol and depending on how far it goes, the wine can end up with varying degrees of sweetness. If the wine ends up really dry (trocken), riesling tends to be very crisp and bright. If you have a wine that says feinherb, then the wine will most likely walk a playful line between actual dryness/sweetness. Remember too that the character of the acids comes into play as to how the wine actually feels on the palate.
Riesling can be light-bodied, or full, viscous, and rich in all it's delicious sweet or dry permutations, you can always ask us about the style of a specific wine in the store.