Don’t be tempted to cut your lawn too short, even if it is knee high! Keep the blade high and then slowly reduce the height every other week. The aim is to try and cut the grass by a third of the height, otherwise the grass will turn yellow.
Really keep an eye out for the weeds, any seedlings should be hoed over, as well as annual weeds. Perennial weeds such as dandelion or dock should be dug out, try and get all or as much of the tap root out as possible.