Seeking advice for holiday trip to Botswana

Dear all, I will go to Botswana for a 2-week holiday trip beginning of next year (hoping that the raining season won't be too heavy...). Has anyone of you already been to Botswana? I would be glad for any advice you could give on what to visit, see (besides the okavango-delta) and what to avoid... And what about malaria, is vaccination necessary? Thanks for your tips in advance, Margrit