What are space-saving DIY wall shelves designs?

[Anthony_T]

I need more storage in my small apartment and I'm thinking about DIY wall shelves. What designs are both functional and stylish? I'm particularly interested in floating shelves and corner shelves. What materials are best for different weight capacities? Any tips for installing DIY wall shelves securely in drywall? I want something that looks professional but is budget-friendly DIY.