hi Gale, i sell shoes and the flip-flops we sell are made to mould to your foot and so good fitting is the key, we also only use leather toeposts as anything synthetic would irritate or damage the skin between the toes, and given u would potentially be wearing them on sand, that would be double the potential damage, a flip-flop should not be too big at the front of the foot, as this could be a trip hazard, but nore should it be too short, which would potentially cause broken or injured toes. the upper on a flip-flop can be made of any material but leather is preferred as this does not cause over heating or swelling especially in a hot climate, leather is more amenable and will stretch with the foot to just the correct mould. Do not be afraid to try flat or deep soled as both have their advantages, it u want a fashionable flip-flop to wear with jeans or say a gypsy skirt, the dark natural leather look with thinner soles are ideal but if u want a holiday flip-flop for around the pool or on the beach, choose a thicker sole with perhaps white or other pastel coloured base.