Nasty looking and irritating, isn't it? Well, without knowing the particulars of your bathroom layout, I can offer some general advice...
The may reason for mildew formation is condensation and temperate climate. Both of these condi
tions occur when moisture is trapped and allowed to remain on surfaces. Since you mentioned that the mildew is most noticible on your ceiling, the most common cause is warm air rising after a shower or hot bath.
The first, and easiest remedy is to
open a bathroom window and allow the condensation to evaporate. (Assuming you have a window and security isn't a problem.) If you don't have a window, I strongly suggest you have a bathroom vent installed. This electric fan can be retrofitted into al
most any layout, and will eliminate the climate which the mildew thrives on. If you already have a vent fan, a new fan can be installed with a higher CFM rating. You may also consider repainting the bathroom gloss enamel with a mildicide additive.