Walking Boots

Your boots will probably be the most important piece of kit that you buy. All it takes is one tiny blister to destroy your hike.

My first suggestion is that if you don't have good walking boots, buy some NOW and start breaking them in.  I wear new boots several days/week for several months before I take them out on the mountain.

Look for good ankle support, something like a vibram sole, waterproof, etc. Personally I wear 2 pairs of socks with my boots (1 thin inner and 1 thick outer which is sometimes referred to as the double-socking method) so if you plan to do that make sure you're wearing them when you try on the boots. And leave enough room in the toes for your foot to travel on descent.

Update: My brother reminds me of a quote from our fave author, Robert Heinlein: "If possible, have your feet clean and dry. Smear your feet all over and especially between your toes with cold cream. Or Vaseline, carbolated is best. Use lots, a thick layer. Then put on socks-clean if possible, dirty if you must, but don't skip them-and put your boots on. When you first stand up, it feels as if you'd stepped into a barrel of soft soap. But your feet Will thank you for it and you won't get jungle rot between your toes. Or not as much. Take care of your feet, Ted, and keep your bowels open." -Time Enough For Love

Hopefully such measures won't be necessary where you are trekking. And I really must read that book again. Maybe I'll download it for Gokyo Ri.