Complex sentence: Her biggest success occurred in early 2015, reaching her first WTA final in January followed by a fourth round major appearance at the Australian Open; in May her ranking reached a career-best of No.35 in the world.
Split into simpler sentences: Her biggest success occurred in early 2015, reaching her first WTA final in January, followed by a fourth round major appearance at the Australian Open. In May her ranking reached a career-best of No.35 in the world.