Home DIY

anyone know the best way to affix a shelf to a dry wall without it (the shelf) sagging? Have tried plastic rawl plugs but they don't seem to have sufficient grip and the metal ones are just far too wide for the holes on the shelf brackett. Help me internets!

They're a bit overpriced but some of the Black & Decker piranha ones are quite decent for this.

I can't remember which exactly but there's normally a big display in B&Q or whatever with a whole selection including some designed for dry wall, the Molly maybe.