To achieve a tousled beach wave, use a large barrel curling iron and alternate the size of each section for a more natural result. Don't be too rigid with the sectioning. Start underneath and work up to the cheekbones, leaving out the ends for that loose, tousled, beach wave look. 

When curls are completely cooled, loosen the curls for a fabulously tousled look with oodles of texture. Finally, spray with a light mist of Sassoon Professional Edit Hold to lock in the waves.