Before setting off: a little foot rub with a pumice stone, nails trimmed ... so many simple actions that reduce your worries once you're trekking. Massaging your feet with creams to prepare for long walks can also help and you should continue this massaging during your hike.
During your trek: don't let blisters start; if you feel friction or your feet getting warm, make sure you take preventive action and use a bandage, protective stick or a strap to isolate the zone and to avoid the blister developing. You can also apply anti-rub creams each morning .
In the evening at the bivouac: massaging your feet with a nourishing cream is a great way to thank your feet for carrying you all day. Air your feet, ideally walk barefoot or in sandals. Dry your socks and take out your insole out to dry off.
Finally take care of yourself, and get enough sleep because fatigue can make the skin more sensitive and promote the appearance of blisters. Remember that diet also plays its part: alcohol makes perspiration more acidic and therefore more aggressive to the skin!