We have a site called Kill Mildew. There isn’t a lot to be said about mildew other than the formula of one part house hold bleach, and three parts water, with a very little amount of detergent as a wetting agent. The solution needs about thirty minutes to be effective.
You can put the solution in a spray bottle, but we also use cloth that is saturated. We wipe down windows, and sliding door tracks. Bathrooms can get a complete wipe down. For some reason kitchens aren’t as bad, but there are areas where the bleach can help kill bacteria.
This time of year when the house is closed up, and the heat may be on is the time we notice mildew the most. You can get started cleaning it up now, but keep in mind that as the spring, and summer come around it would be a better time to open windows, and doors for ventilation, and really kill the places mildew spores may grow.