I always press my kilts on the carpeted floor and always take time to arrange the pleats very carefully before I start the operation. 'Press' with the iron, that is: lift the iron up and press it down again, having moved it a little - and do this through a dampened tea towel or similar. Do not 'iron' with a sweeping movement, because you will move the pleats under the towel without realising it, and will probably end up with your pleats in a worse state than when you started!