Consider the following:
Conferences & Exhibitions: In which case bigger is always better, make sure that it's your bag that all your competitors bags are hidden inside.
Clothes: Men or Women? A man prefers a shorter handle whereas women are happier with a long handle. Lamination is recommended to stop possible dye rubbing onto clothes if you are out in the rain.
Gift Bags: Add ribbon handles or a central ribbon tie.
Food: For takeaways look at our Kraft paper bags or luxurious cupcakes play around with some funkier ideas like small individual triangular or star shaped laminate bags.
Retail: Add eyelets for extra strength and that added little flash, have a look at laminate finishing options to make your bag stand out.