Have done the WHW three times now. My recommendations to you are manyfold but relatively simple. Plan your accommodation around the hillier points of the walk so that you do the steepest bits whilst still fresh. Stay at Drymen before tackling Conic Hill, The Kingshouse Hotel before the Devil's Staircase and Kinlochleven prior to the Mamore Ridge ascent. Much more enjoyable after a good nights sleep
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Best advice of all, take and use walking poles. They take so much pressure off the knees and ankles, especially during the downhill stretches. Most importantly of all get out walking early! We try to be on our way at first light, which means we could be 9 miles down the road whilst others are still finishing breakfast
. A late lunch, with all the walking done for the day, is much more preferable.
Take heed of all of the advice offered about good boots, walking socks, compeed and vaseline!!