During the day, brown shoes are usually the best choice. They work well with beige, navy and blue, and look light next to white. For relaxed occasions such as a garden party, suede is a good choice, for example these dark brown suede loafers. For a more formal daytime event, smooth leather is better. Burgundy is an interesting alternative to brown, and it warms up white as well.
Black shoes make sense in the evening and at more formal receptions. The contrast of white and black is strong, so keep the rest calm: a white shirt, a navy tie, a white pocket square. Classic black cowhide shoes with a Goodyear welt and leather soles suit this kind of outfit.
Match the belt to the shoes: brown with brown, black with black. Do not combine black shoes with a brown belt, because white amplifies any such clash. A practical option is a reversible black and brown belt with a silver buckle: turn the buckle 180 degrees and it changes colour. With white, avoid chunky, contrasting buckles.
Match your socks to the trousers or the shoes, depending on the effect you want. Light socks close to the trouser colour visually lengthen the leg, while socks in the shoe colour put the emphasis on the shoes. The more formal the occasion, the calmer the colour.